Did a festival gig once going through a Bose L1. Amp in a room, or FRFR? I dunno, but what was really cool was with that column speaker, I could place the guitar parallel to the speakers and get awesome feedback :) It felt like I had more physical interaction with that amp than I'd had for a long time with an actual guitar amp. But to be fair, it also had a bass bin that was blasting air, like an amp.
Frankly, if only guitar amps existed, I'd play through guitar amps. If only Helix and FRFR existed, they I'd play through that. Maybe I'm just not that much of a "feel" guy. I played through guitar amps throughout my high school and college years but when I went pro, I went direct through keyboard amps and never looked back. Because I straddled the world of studio/live, it was the perfect solution because it worked for both. So, when modelers came out and would let me take that to the next level, I was already primed.
This isn't to say that the feel of a guitar in a room isn't cool. But bringing the sound of the studio to the stage can be pretty darn cool, too...just in a different way. I've experienced both, and I truly believe it's a matter of personal preference.