Out of Saturday boredom, I hooked up my Axe-Fx 3 to my BluGuitar Amp 1 ME's poweramp, which is then connected to my BluGuitar Nanocab + Fatcab 1x12 pyramid.
Trying the different amp models on the Axe-Fx just really shows how big a deal the cab sims are. Only the most extremely different amp models sounded noticeably different from the BluGuitar's Fender/Marshall preamps. Vox, Tweed Fender style amps, Recto...everything else kind of turned into a "Marshallish thing into Greenbacks" because the cabs stay the same.
I was running the full amp models into this rig, but I also tried a bunch of them with preamp only. JTM45 was probably the most drastic, it became a straight up clean amp with poweramp sim disabled. The more interesting ones were the Marshall JVM and Friedman BE models. Turning the poweramp sim off on those made an absolutely minimal difference, just showing how much of their sound is from the preamp.
Obviously when going into cab sims that poweramp sim is still important because it's doing all the stuff the real poweramp is handling in my setup.
But this little test just puts me even further into "it's all about the cabs and speakers" camp where a Vox isn't the classic Vox tone without Celestion Alnico Blue/Gold and so on. Which was pretty much my expectation as you can easily try the same thing in the digital realm by swapping amp models into the same Dyna-Cab, then swapping Dyna-Cabs with the same amp.