Re: What tuner do you use?
I used a Sabine ST-1000 for years. It was fine for what it was, and for when it was.
Then came the Arion Stage Tuner. That was an OK tuner, It sort of worked like a TU-2, you'd step on it- it would cut your signal, and you could tune... But you couldn't tune to anything but E, A, D, G, B and E with it- no half steps... Besides that, because of the location of the LED window- it was difficult to tell where center was. The battery cover sucked. Again, for it's time... it was OK.
The whole time I'd always wanted a Boss TU-12. Those were the tuners all the cool players used. I finally got one, it's great- I still use it, but I was spoiled by the Stage Tuner's muting.
Then came the TU-2. Awesome pedal. For the combination of price, ruggedness, compactness, ease of use, accuracy... it's awesome. It may not be as accurate as some (expensive) tuners- but IME and IMO, it's accurate enough to get the job done, and it's lack of accuracy wouldn't be noticed by 90% of people.
And the rack mounted Korg DTR-2. I really don't like this tuner. I've said it's "too accurate." In other words you spend a lot of time bouncing between flat and sharp, and never "on." The LEDs on either sides of flat and sharp seem to have a pretty wide range. In other words, if your're one LED off, it could be a little off- or pretty off. The way I've dealt with it is to balance it with the green light on, and off one LED to either side. In other words, somewhere in the ball park.
As far as how much accuracy you need from a tuner... A few years ago I did some recording at a world class studio- a lot of records you all have heard have been done there. The engineer pulled out a Sabine ST-1100 and "suggested" we all use that tuner. The engineer "strongly" objected to us using one of our tuners... For whatever reason- that cheap Sabine tuner, may not be the world's most accurate tuner- but it does the job well enough for "big time" bands in the recording studio.