I picked up one of these earlier in the week and I have to say they're pretty good and very handy. It's well-built and sounds great on its' own - the initial idea was to have it on my board to take care of those occasional effects. However, of late I've been rehearsing most nights as I have a big Christmas show coming up and was getting fed up of carrying around my laden Pedaltrain Jr and a guitar on the tube, particularly late at night, but this thing coupled with my Xotic EP Booster and plugged into a rehearsal room Fender Twin is covering the lot from Motown, funk to Audioslave via Donny Hathaway, Beyonce and Amy W!
Whilst I haven't had too much time to experiment with it on my true-bypass board, I can't hear any sound loss, deterioration or digitising of my original sound, but for best results you do need to "knock out" things like speaker sims etc and just leave the essential effect there. For me, the default effect will probably be the fab auto-wah/filters but the compressor, modulation effects and reverbs sound great too and I could easily find a use for them but I just need to find the best placement for this pedal, especially if I'm using various effects that would otherwise be in different places within my chain. The octaver and pitch shifter are a bit ropey but amp models are fine, particularly the cleans, and with up to 6 effects (aah) allowed, it's pretty powerful (big mA draw of 500 so batteries will die very quickly). It's easy to navigate the menus, the effects are fine and even though there's one stomp button, you can program it to cycle between 3 different settings i.e clean, crunch & lead. The tuner is suffice and certainly won't replace my Polytune Mini Noir, but for £85, getting several good and useable effects is a no-brainer for me and the rest is just a bonus.
IMHO, this is one for the Crimbo stocking but check one out anyway to see if it suits.
True you can get the G3 for not that much more but I think the draw with this is that it's a single normal size stompbox footprint that allows so much. I think it's a great idea and hope to try one out soon.