I’m a beginner who’s been struggling along with my nickel Generations and Walton nickel and brass whistles since I started. And I do mean struggling. I’ve made several posts for help to see what I was doing wrong. I called my whistles “tempermental,” and that suited them just fine.
I got a bargain on eBay, and an absolute gem of a whistle arrived today and I haven’t been able to stop playing and marveling at it. Not only is it pretty to look at (black with an ivory colored mouthpiece and gold label), it’s pretty to listen to and a joy to play. Here’s my impressions of Walton’s “Guiness” Black Whistle in D (aluminum):
Considering the tone of my Walton’s brass as “warm” and that of my Generations as “cold,” the “Guiness” is “cool.” It’s sharp and crisp without being strident, but still has plenty of chiff. It’s nicely in tune with itself in both octaves and plays a pleasant Cnat using fingers 2 and 3. It doesn’t have a lot of volume, but I have several whistles which are quieter.
It takes about the same breath as my Walton’s brass (which is less than any of my Generations), but responds to tonguing much better - there isn’t an initial “burp” even if I tongue too hard (as I do sometimes, dash it!). Also, the breath pressure needed to play the upper octave graduates nicely; on my Gens, particularly, there is a considerable increase needed between upper octave G and A, another big increase between A and B, and you can just about forget anything higher than B without gulping more air. The Guiness, however, is much more even. One of my favorite songs is “Carrickfergus” and the “high part in the middle” sounds like it belongs in the song when played on the Guiness, but tends to sound like I’m practicing for a pig-calling contest on my Generation D, and my brass whistle doesn’t like it at all.
It’s really responsive between notes, doing big jumps evenly, and I’ve even managed to slur up from a lower note to the second D without a squeak, but still need to practice that - at least the Guiness will LET me practice. Slurred or tongued triplets are nice on the Guiness, my Gens have a tendency to not sound either the middle or the last note; I thought it was me, but apparently not entirely; now I can concentrate on my fingering instead of just getting the stupid notes.
It plays well outside and doesn’t seem to be as sensitive to either the wind or changes in temperature and/or humidity; it may be the aluminum shaft.
But oh, dear, the Guiness is still a “cheapie,” and unfortunately there are a couple negatives:
The black finish is sprayed on, and not very expertly. How do I know? Because there are tiny bumps in the finish and splatters of black under the holes. It either isn’t affecting the tone or is adding to it, so I’m not really concerned about this except that it’s kind of non-aesthetic. Also, I expect that the finish will chip sooner or later. Of course, that will indicate that the whistle is often-played 
Walton makes a thick paper label that isn’t glued on very well - the labels for my Walton’s D and C have already come off, and the Guiness label will probably follow suit soon. I hope not because it adds to the over-all prettiness of the whistle.
Being aluminum, it is VERY light weight; it weighs less than my Gen nickel “G,” which is an itty-bitty thing. However, it seems to be quite well balanced and I soon got over the feeling I was going to blow it out of my mouth.
All in all, I’m extremely happy and wouldn’t hesitate to recommend this as a beginner’s whistle or to someone to add to their whistle collection. It has a nice tone, plays well, and looks quite dashing.