I recently grabbed a (slightly used) Boss TU-3 for like $66 from GC a couple months ago. (A used TU-2 would be even cheaper).
The boss TU's have been reliable go to Pedal Tuners for years.
Nothing wrong with the TU-2 (or even the 1st one), BUT I'd rather a Used TU-3 than a new TU-2. Apparently the 3 reacts Faster, is easier to see and is even
More accurate than the TU-2.
That said, I've never "
NOT" been in tune using the TU-2 (or 1).

But "more accurate" must be better, right?
That's my story and I'm stickin 'TU' it.

T$