My ST-200 has been bouncing around my gig bag for 8 years now and it still looks and functions like new.
Tracking, accuracy, readability are all tops and the battery drain is minimal.
I also have a Korg Pitchblack tuner pedal and I like this unit much better in pretty much every way. (The Korg is more intuitive to calibrate but I never use that function.)
Sonic Research Turbo Tuner ST-200