Fairly new owner here and for the most part, I can appreciate the overall frequency output of the helix for its flexibility. Running into the OT of a 100w marshall SLP, the presence knob on the amp allows for great "stage" tones, while an IR'd signal can be sent to FOH out the XLR's. IF i use the globals, they're only applied to the XLR and matched to my on stage cab. Room matching is a collaboration w/ the sound tech at the venue.
That aside, I like to view the Helix "Environment" as a portable studio setup for a guitar rig. Bussing (somewhat),blending, crossover, EQ, compression, etc. can play a huge roll in how the unit sounds and feels. CAB blocks directly after the amp and before an IR can really focus a tone when blended the right way. Of course, there are infinite shades of "good enough", but amp and cab sim is a small part of the overall achievement of tone w/ these bad boys.