Well, there are two basic kinds. The pseudo-strobe ones (like the Petersons) are pricey and truly more accurate, then there's all the others which use the exact same technology. So what do you want to do with it? If all you need is one to get the instrument into tune, and you don't need see it on a stage, the lower end ones all work the same as the higher end ones so get a Qwik-Tune or something like that.
If you're gigging, then there's a good reason the Boss TU-2 is so popular. It's rugged, it's accurate (at least enough for tuning, but IME not for doing set-ups), and it's easy to see on a lit stage. ANY decent LED is visible in the dark, but what happens when you're doing and outdoor gig in the sunshine- can you still see the LEDs through the glare? That's why I love my Boss TU-2 tuners.
However, if you want to do set-up work drop the cash on a Peterson. The difference in accuracy is critical. The standard Seiko chip that everyone uses for regular tuners is accurate to ± 3 cents. So the tuner will show "In tune" if the note is anywhere from 3 cents flat to 3 cents sharp (there are 100 cents in a half-step). That's not noticeable to most people when playing with others. BUT- if I'm setting the intonation and comparing two notes on the same instrument, that ± 3 cents means when I play the open string it could tell me it's in tune when it's 3 cents flat, and that the fretted note is in tune when it's really 3 cents sharp- that's a 6 cent range of error which probably WILL be noticeable, and it will make the other fretted notes out as well. With a Peterson's ± 0.1 cent, it will can tell you the open string is in tune when it's really 1/10th of a cent flat, and the fretted note could be 1/10th of a cent sharp, a total error of 2/10ths of a cent, which is more accurate than most human ears can reliably distinguish.
So, it depends on your needs.
John
but I am not looking to get the cheapest possible either.
