EDIT: After using this tuner for some time in real life situations (gigs, studio, rehearsals) I've decided to lower my ratings considerably. The green middle LED is so much brighter than the adjacent blue LEDS that it completely overpowers them, It's very difficult to see the innermost blue LEDS when the green LEDS lights up because you are practically blinded by the extremely bright green LED. It's therefore difficult to see if you are in tune or slightly out of tune. This is a VERY flawed design. The regular (much cheaper) non-Waza model with the red LEDS is a lot better. Don't waste your money on this one!
(My original un-edited review follows below):
I got this to replace my old Boss TU-2. I wasn't sure if I should spend this much or get the regular non-Waza TU-3. Curiosity got the better of me so I got the Waza.
It's a very good tuner. It reacts considerably faster than my old TU-2 an it's also slightly more precise. It's not TOO precise though. I used to own a Sonic Research Turbo Tuner which to a lot of guitarist is THE best tuner out there. While it may be the best tuner based on specs it was just TOO precise for me. I mean, who really needs +/- 0.02 cent? Tuning took forever because it was almost impossible to make the lights stop spinning. I ended up selling it. The Boss TU-3W on the other hand is just about perfect. It's precise enough for any practical purposes and you won't waste time trying to pin down that last 0.02 cent.
Boss tuners are often criticized for their buffer coloring the sound. I've never found this to be a problem. Quite the opposite. I find Boss buffers to be much better than their reputation and so is the one in the TU-3W. But if you don't want the buffer in your signal chain the pedal can be set for true bypass too. And to be honest, that's probably the only really significant thing that sets this Waza apart from the regular, much cheaper non-Waza TU-3.
Is true bypass worth all that extra money? I guess that depends on how you set up your pedal board. If you don't really need true bypass you might as well get the much cheaper non-Waza TU-3.
Any cons? Well yeah, just one: The Green center LED is so much brighter than the blue ones that it can sometimes be difficult to see if one of the blue ones right next to it light up (meaning you're not perfectly in tune). This won't be a problem on the non-Waza TU-3 that uses green+red LEDs instead of green+blue. They should have stuck with the red LEDs on the Waza too or made the blue LEDS slightly brighter.
To sum it up: The TU-3W is a somewhat overpriced but very nice tuner pedal.