Hi, the grail would exist for me, if there’s a well formed whistle tone all over the scale in the same volume.
Take guitars. Difference is mostly the pickup, tension of strings, playability, wood quality… Or fiddles, mandolins, banjos, saxophones, pianos. In my experience no kind of instruments like whistles are more different. Some fipples simply don’t work, some work on every body. But I’m sure there must be a rule, a formula that would work to create the grale.
Like most of us, I have personally bought and sold a ton of whistles. I’ve regretted selling a few, regretted buying only a very, very few, but did finally find my holy grail of a whistle…an O’Brien 3 piece delrin rover. Tuning is great, not too loud or too soft…and it has a full, buttery-soft sound that is what I have always dreamt of! Plus, it comes apart for easy travel/storage into three pieces, which makes storage in varying flute cases really easy.
Eric
For me, the perfect whistle is the next one I buy!
Speaking not as a professional musician but as one who occasionally soothes his soul with slow-aires, I chose Burkes. As Richard said, “….Burkes have such smooth voicing over the gamut, and mostly perfect tuning.” That degree of refinement and their jewel-like build quality is why I prefer them. Simply handling them is joy. I’ve owned instruments that cost more and many that cost less. When my whistle accumulation began to own me and I had to deal with the dilemma of down-sizing, parting with the Burkes wasn’t even a consideration.
I also had a Burke high D. And sent it back. I cannot agree it’s really worth the money. But that’s only my opinion.
My first whistle that I really liked and dubbed ‘good’ (to my tastes) was a Burke in A. Which I still have and have no plans to ever sell, even if I ever get another A. It holds special value. I love and hate Burkes. They play so cleanly. Maybe a super advanced player wont appreciate that, but as someone who completely sucked when I got it, and is now maybe an intermediate player, I still appreciate it. It gets better as I get better while removing some bad sounds I could make if it was a harder to play instrument. Which just makes my perforce the best it can be. The craftsmanship is stellar. And they have 0 moisture issues, which I have issues with on many other makers. Burkes do use more air and take a bit of push than other whistles. The push doesnt bug me. And the air use doesnt bug me on the smaller whistles. But low F and down really bugs me. And it makes me sad because if he just made the airway shorter, and just kept it the same as like on the A, the low whistles would be excellent. But I just cant get over the insane air inefficiency. I saw a burke high d for sale a while back but didn’t buy it because I just don’t paly high whistles. But I’d probobly like it. Burkes dont have the most special tone, but at the same time theres somethign to appreciate by the cleanness of the tone. Its so clean that it actually makes it a unique tone vs other whistles.
I feel a bit like an old-timer in liking O’Riordan whistles, which I don’t think have been mentioned here. I started playing for my own enjoyment and later on a few weddings, etc., in 2006 I believe it was. I bought and sold many whistles over the years, and ended up with a collection of Pat’s whistles in several keys, low C, F, G, A, Bflat, and c, d, eflat, and a few odd sets with multiple bodies, and a very early wood set that includes a flute body. I wouldn’t claim they are the ‘holy grail’ by any stretch, but for me, I still find them easy to play and they were made by a great guy, may he rest in peace. There have been a few along the way that I wish I’d kept, too. I owned at various times 3 or 4 ‘Greenwood’ whistles by Michael Boisvert that were very much O’Riordan clones from a construction standpoint, but all in interesting wood species, and one of them in particular that was purple gidgee as I recall, stood out among the crowd. It had a clear very ‘pointed’ tone that was loud enough to peel paint from the walls. There was a low F and high D by Michael Grinter that was as beautiful as whistle making gets in every way - visually and musically, at least IMHO. I’ve hung onto a small scale brass D by Mack Hoover that has a tiny, sweet voice that taught me a lot about breath control, for sure, and a Glen Schultz Water Weasel gray PVC in “A”. I’ve spent a lifetime doing pipe organ work and voicing, and while I could get a little hung up on the nuances of tuning, I don’t because most of the repertoire doesn’t lend itself to long, sustained notes where it would be most likely noticed, at least, IMHO. For a tube - of metal or wood or plastic - I think a little latitude is in order.
They’re not my cup of tea either, though I was enamoured with them at one point.
What I’ve found in doing Studio gigs and Church gigs and such, where I’ve chatted with a number of professional non-trad (“legit” as they say) musicians whose primary instrument is Boehm flute, Recorder, Sax, etc and who regularly “double” on whistle, is that musicians coming from a non-Irish-trad background are usually looking for rather different performance characteristics than Irish trad musicians.
These people usually love Burkes, sometimes even citing as desirable the very traits that Irish trad musicians will cite as objectionable.
What specifically didn’t you like about the Burke? Was your whistle the Session Bore, or Narrow Bore? Was it alloy or brass?
I owned two Burke High D’s, quite different: a Session Bore alloy, and a Narrow Bore brass.
I feel like this is exactly why I hate Gen, Feadog’s, etc and love whistles like Burkes. I dub whistle my primary instrument but I started on piano and guitar, and have no traditional Irish background. I didn’t even know what an Irish tune was until I started playing whistle and started spending time on this forum and watching whistle review videos. Which would make most people wonder why I even started the instrument haha. How burkes play, minus the insane air use, is exactly what I’m going for.
In my life I played a lot of different instruments. Guitar, Bouzouki, Mandolin, Piano, Boehm flute, from violin to double base, Clarinet and so on. My case is playability and a fine characteristic tone. And quality, of course. And that’s why I tried a Burke (Session brass high D). Unfortunately it had a poor playability and a tone without soul. I cannot say anything about the workmanship. But you can be sure I would have been proud to own a Burke as a little treasure.
Sadly in this case it’s not right: more expensive = better quality.
Unfortunately it had a poor playability
How much time did you give yourself to get to know the instrument?
I am no fan of Burkes but poor playability?
Often, too often, I see people here sell whistles saying ‘only played a few minutes’. I scratch my head and wonder at that sort of thing. It can take a bit to get to know an instrument, especially when you are a less experienced player.
And regarding the ‘stellar craftmanship’ above: that’s cnc machines for you. 
As a longtime flute player I will say that it would take me around a week of daily playing for my embouchure to fully acclimate to a flute.
However at first blow I learned the fundamental characteristics of a flute, say by playing up and down the scale.
To put it into numbers (a bit silly I admit) I would know 90% of the flute’s behaviour immediately, but that last 10% took several hours spread across several days. A flute embouchure is a complicated thing involving tiny adjustments in a large number of facial muscles, and for me it took time.
Whistles don’t have that; their tone production is predetermined by the maker, and every detail of how a whistle performs can be understood in a few minutes of playing.
On the other hand I’ve discovered that if I devote myself to exclusively playing one whistle for a few months my style slowly adapts to what that particular whistle likes to do. For example when I played only a Burke Low D for a few years the fact that it required frequent breathing and that Bottom D was by far its strongest note, so that I could really lean on it and “honk” it, I found myself playing in a style somewhat akin to some of the old-time flute players.
When I switched to an MK, which was extremely air-efficient and had a weak Bottom D, my style evolved to longer smoother phrases.
I should stress that as soon as I played a Burke and an MK I fully understood how these whistles performed; they didn’t perform one whit better for me after five months of playing as they did after five minutes of playing.
So this is your opinion, Mr. Gumby. Without trying the whistle I had.
I wouldn’t rule out I had a whistle of lower quality. And… I wouldn’t send it back for fun by losing about 40 $ for shipping.
So I guess I know what I had, what I did and what I’m talking about.
People who’ve bought a new premium whistle and are unsure of keeping it after playing it for 13 seconds,
should send it to me with $58.75 and I’ll give the whistle a thorough test and return it with a
25-point detailed checklist with insightful comments about each feature and factor of playability, so they can
have more suitable data with which to make rash decisions about totally subjective concerns. 
In addition, if during or after this process they decide they really don’t like the whistle and are profoundly appreciative
of my participation in their reckless behavior, they can send me the whistle to keep, for free
and I will promise to never contact them about that whistle again. 
I might just extend this offer to owners of Ludwig drums, high-end guitars, Bosendorf pianos, Bach saxophones,
Korg and Yamaha keyboards, and for new owners of parrots, Kawasaki motorcycles, trampolines, motorhomes
and mountain bikes, for starters. 
In support of Mr Gumby’s point whenever I have purchased a new whistle - and there has been a few - after an initial play I have generally put the whistles aside with a bit of disappointment that they had not played like I had expected and hoped. After time I have given the whistle(s) another try and put them away again. That dance has gone on for a while until one day I have picked up a previously abandoned whistle and said to myself, hey that’s a nice whistle. That’s me adapting to the whistles not the other way round.
Cheers
So this is your opinion, Mr. Gumby. Without trying the whistle I had.
Whatever else you feel about them, Burkes are not known for inconsistency, if anything, quite the opposite.
They consist of parts made by cnc machines, which are not known for errors or irregular output.
Any Burke I ever tried, admittedly not a large number but perhaps half a dozen Ds, a C and a B, played pretty much like the others.
The likelihood of a very poor one leaving the factory is remote. So yes, with all that in mind, that’s my opinion.
Same here. Funny how the “dance” goes on and you have a different opinion about that whistle. I have quite a few high D’s now, and they all take their turn as to what hits me as the best one at that point in time, even if for only one tune.
So what’s the reason for the price, if some machines cut some brass?
Yeah, nice product placement. I’d do the same.
Whistle making sounds a little like a religion.
Something like… you pay for names like Gibson, Mercedes, Adidas… if the quality is (still) high or not.
I play several whistles, kept the ones that are good for me and sent the others back. I don’t expect much for 10$, for 300$ I do. Don’t care for brands.