I use this with several guitars, mainly a Fender US strat, and also as a send fx for recorded non-guitar stuff which is fun. As far as the guitar sound it is really good for the way I use it - straight to the board. The basic tone is very well preserved through the unit when running it clean, which cannot be said for my J-station or the Pod which I used to have. I also like the distortion a lot, but I may differ from most people as I generally prefer transistor/stomp dist (or digital in this case) to tube dist, except maybe for semi-overdriven tones a la Fender combos or similar - I don't like 'fat, warm' sounds... I want it cold and lean, he he. More experimental than virtuoso dist if you like, and this unit is fine for that I think. The reverbs are surprisingly fine as well for a guitar unit, as are delays and chorus, absolutely usable for other stuff.
Well, I got it second hand, and the display is kinda weak and hard to read sometimes. Except for that, the build quality is like most professional units.
I bought the unit unheard on reputation alone, and for the price I would have accepted anything I guess. But I like it a lot and have been using it quite a lot during the last months, mainly as a quick n'dirty headphone practise amp, but also as a mix toy. Recommended.