Never used the Digitech, but I can say the Xpression is a great unit and it is almost totally transparent sounding. I found some of the Chorus/Flange parameters a little confusing to tweak. However, I have little patience and hate reading manuals
I plan on picking up another one soon. I would say you can't go wrong with it. The quality/durability sure beats the hell out of both TC Electronic units I had. One of them had knobs falling off and a non functional mix control............the other one died after 2 weeks.