I find the helix reverb algorithms are not bad but not fantastic either. I don't have much experience with Line 6 reverbs in particular. I have several dedicated rack units that sound better to my ears (I think it is subjective). But when you consider you don't have carry around a rack and deal with the challenges that brings (grounding, signal levels, impedance, midi, RF, setup tear down time, medical expenses from breaking your back etc) that's pretty huge. Also live you are probably going to apply reverb at the console so the guitar sounds mixed like it is in the "same space" as the rest of the instruments. For recording you are probably to track the guitar dry for the some of the similar reasons.