I have been using a tuning app on my Android to check the tune of my high D, but I’m finding that the results are neither repeatable nor particularly accurate. So, I have decided to purchase a dedicated tuner - which ones do you love or hate?
Thanks for the advice!
cheap at twice the price!
http://www1.ocn.ne.jp/~tuner/tuner_e.html
I’d second that nomination. But for an Android, the coolest app I’ve seen has got to be the PitchLab tuner. Same price as syaku8, and some really cool additional features. No dedicated device can match it.
My thanks to you both!!
The obvious smart-a** answer to your title question is: your ears. 
As a commercial product, I like the Peterson strobes - hardware, software, mobile. I find the strobe interface very intuitive. But no Android version yet.
Heck, I like my original Conn ST11 Strobotuner, too. But I wouldn’t recommend carrying that around. (Hint: 10 lbs). 
I would caution that if you’re not getting reproducible results on tuner X, then tuner Y or Z may not help. Consistency is up to you, and you need to find the right breath plateaus for each note, else tuning your whistle to a G or A or whatever won’t give you the intonation you need.
You might really want to play with the Flutini app, which gives you a real-time inventory of your pitches. Don’t have time to search the link; maybe someone else can oblige …
As Brother Steve says “Although in general, people with perfect pitch do not take up the tin whistle!” - I’m pretty sure he was describing me in particular. 
They seem to run at about ~$25/pound, so it costs even more than lunchmeat, but it is quite pretty to look at!
Very good advice - thank you! I performed a somewhat controlled (and simplistic) experiment on the software by using various tones generated by my PC to make my decision. I had been getting swings of 50+ cents while practicing and suspected that even I’m not that bad… 
I have an “entry level” Android that seems to get bogged down by the simplest of activities, so I suspect that the sampling is being distorted by the processor bogging down.
I’ll find it - thank you again!
On my droid razor Marx I have DaTuner lite. It is free and works well.
Ron
I use a prog called G-Tune for PC, I think it was a paid program. I can never understand how people can tune with those needles flickering all over the place. With this prog you get a scrolling graph and as you can see from my image it’s pretty consistent even though I did this quickly without much care just to get the image up here. And it is accurate as I play regularly in sessions and sometimes the fiddle players will even tune off me by ear.
Interesting. It’s this, I guess: http://www.jhc-software.com/gtune.shtml
They’re also apparently the programmers behind the Peterson software strobes.
Actually, the Shaku tuner also has something similar to the real-time stepped display. And IIRC you can save off the data for further analysis in Flutini etc.
Yeah that’s the one. I like it because you can visually see the tuning throughout both your octaves and decide where you want to balance it. You know the way with some whistles you could be bang on at the bell note but as it gets up into the second octave you can see it getting gradually flatter. With this you can see exactly whats going on all on the one screen. It’s handy for example with whistles I have that I only use to accompany singers and would never go above say a high G, therefor I’d tune to get the best balance for that range of notes.
Many thanks! Now I have lots of new gizmos to play with - now if I can just find one that I can convince that I am perfectly in pitch I’ll be set! 
MT, have you tried the Peterson strobe clip tuner? i’ve read mixed reviews. it’s about 4x the price of regular clip tuners (Snark/Fishman are $12-17, Peterson is $60-70) i wondered if it was really that much more accurate.
i’ve used traditional strobe tuners (the big ones) and been happy with them.
also, i guess clip tuners aren’t preferred for whistles 
No, sorry, not the clip, only the handheld or iPhone. For guitar I use a cheapie clip-on. Which sort of works if you clip it to a small whistle, but it’s clumsy. And of course, it’s trying to sense mostly the tube vibrations.
I use the Peterson strobe clip tuner when I’m adjusting guitar intonation (on electrics and floating-bridge guitars, or combos - they can be tricky). For the last little bit. For general use I would say the Snark tuners are the best ones I’ve tried, they’re very accurate and they don’t flicker around the way the Peterson strobe tuner does. But for that last little bit.. the Peterson does the job. For ordinary tuning I don’t normally use a tuner, but if it’s noisy and I need a tuner I would grab the Snark before the Peterson.
I have checked/compared my whistles a few times (there were some threads about whistle intonation a while ago), for that I used a Snark tuner. I buy the red Snarks, those which have a little mic in addition to the vibration sensor. They work fine for whistle (and that little mic made the one I accidentally broke off its clip still useful - better for whistle than the clip-on, in a way, because it can be put flat on the table). The daTuner application on my Android phone is not bad, but the Snark is better.
-Tor