From an old post I made on another forum:
"It’s quite good at lower gain stuff and the effects seem pretty good but I can’t get a high gain sound I actually like. At least not compared to the Vypyr 60. On the Catalyst, the low end is comparatively anemic, I can’t get the mids to sound even decent, and the high end doesn’t seem pleasant.
To reiterate, I’m just talking high gain. I haven’t tried it with pedals yet so it might be okay with those."
But I believe there were some changes made after I tried it. For example, I read they added the Badonk amp which could definitely address my problem with the Catalyst's high gain.
Also, I still have and love the Peavey Vypyr 60. That thing sets a really high bar for modeling combos imo, especially with the effects loop mod which was necessary for me regardless but also makes it play quite well with the FM9. I have yet to find another modeling amp that I like as much as that one.