I've got a TU-3, a Korg Pitchblack (standard), and a Polytune Mini Noir...
Even though the little black rubber washer holding the battery screw is broken (so when not being stepped on its always a little further open and shows the empty battery compartment and guts) I usually end up using the TU-3 the most. It reads fast, is easy to see, easier to step on barefoot or wearing platform stillettos, and the power thru ability almost always comes in handy.
The Korg also has that power thru ability, easy to read screen, and is better looking overall but a bit slower than the TU-3, and the last few times I plugged into it before loaning it to our guitarist I felt it wasn't quite as accurate as the Boss or the TC (i told guitarist to test it against a known good one and he swears it's accuracy is fine.)
The TC is quick, accurate, and very easy to read for a compact tuner. It's usually my first choice for my small board that I'll be daisy chaining power to. It's lack of a power thru feature is what made me pick up the Korg.
**As an aside, I wasn't aware that those power thru features were limited in terms of mA available (did I read that correctly on page one?) I'm surprised because before I got under board power supplies I was sometimes daisy chaining up to 8-10 pedals by plugging the Pig Hog one spot directly into the tuner, and then chaining the rest from their power out.**