I use an Epiphone Les Paul Standard with EMG81 pickup in the bridge position. It's a bit muddy but not very bad. In my opionion Artist's sounds' and effects' quality is good. Maybe the pitchshifter should be a bit more accurate when in fast mode. Mainly I use flanger and it's a good flanger.
Distortion is VERY good and amp sim is VERY good.
Watch out and check them now and again. It is very easy to get a really good sound of it right from the start. The factory presets I like mostly, some are worthless, some are really excellent. I have also a problem setting up the Ernie Ball pedal which comes with the unit, but I think I will solve it in the near future. I play the unit through the effect Return of the loop of my Marshall TSL 60.