To be honest, I'm not sure what to say about this item. I assume you are all familiar with the "cockroaches and the Boss pedals" story which, speaks volumes but, I don't need to repeat it, do I? The same goes for the reason(s) why a Boss tuner should be the first pedal in the signal path on your pedal board (pretty much, although there are a few exceptions); so no point going over that again. So, what can I say?; other than: o1/ It's a Boss (say no more, right?), o2/ For me, the TU-3 made sense (although there are other models), o3/ It works for 6-string guitars as well as 4 and 5 string basses, o4/ It does lots of other stuff too; but you know all that, right. Hence, I can only tell you what you already know: If you need a tuner, buy a Boss.
PS: I can't actually verify the cockroach story, but I am building myself an igloo out of Boss pedals so, when the time comes ... well, I guess, all my friends will be cockroaches ... perhaps I should rethink that.