I'm borrowing my buddy's FM9, and the thing is amazing. It takes some googling and watching a few Leon Todd videos because out of the box it sounds like ass through a poweramp and cab.
I knew I was doing something wrong because no amount of tweaking the tone controls could fix the issues I was having with it. Turns out you just need to tweak it in other ways first.
I've A/B'd it through the same cabs using an amp switcher, and I've had a similar experience where it's been able to get close enough to a Splawn QR, Bogner Goldfinger, and Mark V.
The biggest difference I've noticed is in the "punch". I might just need the right poweramp, but it doesn't thump like a tube amp. It has plenty of low frequencies, but they're the kind that shake the house vs punch you in the chest.
Still, it's amazing how great it sounds, and there's times where I've preferred the tone of the FM9 vs the real amp. I wouldn't 100% ditch tube amps for it, but would definitely go down to just a couple favorites and this thing.