First of all: with the helix use IRs. The internal cabs are better than the 11r ones but are not good enough, imho.
I have a helix and I had an 11r and I prefer the quality of modeling of the Helix: the amps that really shine imho are the archetype (archon), the badonk (line6 model) and the drz.
The slo on the helix sounds better than the one in 11r.
The choice of fx is huge and the quality is great.
I loved my 11r, but I don't miss it at all (except for the ecstacy model, well, I really miss it )