I have a Headrush frfr112 as well as a QSC CP12. The Headrush sounds good up until you get to gig levels and then I feel like it starts to fall apart a bit. If you can swing it the QSC stuff (and a few others) for a couple hundred more perform a lot better if you are going to gig. If not the Headrush sounds great at home and up to reasonable levels.
This is exactly my experience and, interestingly, I just did some A/B testing yesterday with my Headrush 108s and a borrowed Katana 50 (mkII) yesterday. Bottom line: I'm sticking with the Headrush, with the exception of specific high volume, no FOH set-ups (see below).
A bit of background/context. I love my FM3, and with the funk/jazz band I play with, we all go direct, play with in-ears and FOH (though we haven't properly gigged yet). All seems perfect there. I've been slowly tweaking parametric EQ and playing with IRs to get things right and am super happy.
However, I also routinely gig with an 80s-style metal band (Judas Priest, Ozzy, Maiden, originals). To date I have gigged exclusively with my Katana 100 2x12. That has worked like a champ and the Katana seems to cut through that mix very well (the other guitarist plays through a 5150 2x12, usually too loud) even at the 50w setting. We've played a few gigs with a decent FOH (where they have run both direct out and mic'd the Katana), but a lot of times we play parties/gigs without a PA (yeah, I know). And we tend to play VERY loud.
I have been dialing some super sweet Friedman tones with stereo delays and what not, hoping to use that with this metal band, so I bought a pair of 108s. At home I the 108s seemed like they'd be plenty loud, but at rehearsal they just got drowned out. I ended up clipping them both trying to get anywhere near decent volumes. It was pretty frustrating and I ultimately decided to just go back to the Katana.
I then started playing around with running the FM3 into the Katana and got some good results by not using a cab sim and using a parmetric EQ. Since I wanted a stereo rig, I looked into adding a Katana 50 for stereo effects (or maybe replacing the 100 with two 50s), but after goofing around with it yesterday, I'm punting on the idea.
The bottom line is that, while I liked the sound of the 2x12 with the FM3, the 50 just didn't sound good. Part of this may be that the speaker isn't broken in yet, but I think that little cab on the 50 just has its own sound. I spent a lot of time with various presets testing it out and I just couldn't dodge the "flavor" of the 50. I then went back to the 108s and it was just so much better sounding, especially when tweaking the EQ a bit more.
Anyway, the take away for me is that for getting quality of tone, the 108s are worlds better than either of the Katanas (since you can really leverage the IRs). But if you need a "amp only" set up at high volume, they probably aren't going to cut it. It's not that they don't give you that "amp in the room" feel, it's just that they don't seem to have the balls for high volume application. I'll just stick with the Katana for that. I do think that if I jammed/played with folks at a reasonable volume ,the 108s would be plenty loud/cutting.
As an aside, I played a bit with a kind of wet/dry set up with the Katana 100 and the 108s which ended up sounding really good. Basically, I run Out 2 into the Katana without cab/reverb/delay and run Out 1 through the 108s with cab/reverb/delay. I ended up getting some pretty monstrous sounds out of that and may test that in the rehearsal/gigging situation soon.
