I’ve tried FRFR (but not expensive FRFR), tube power amp and cab, and solidstate power amp and cab. I think the best solution is solidstate power amp and guitar cab.
With FRFR I just kinda felt disconnected, and it wasn’t as chunky or dynamic. Also I spent more time flipping thorough impulses than anything else. I can see the benefits if you’re gigging and want to send a signal to FOH, but it just wasn’t for me.
Tube power amp can sound cool but it depends on the power amp. I’ve used amp FX returns and my 2/50/2 rack power amp. The 2/50/2 is the best tube power amp I’ve tried with it as it is the most neutral, but it takes some fiddling to get it to sound its best. Into an amp, especially something like a Mesa that has a very coloured sounding power amp, I didn’t like it as much. For instance into my recto’s power amp it sounded great, but every patch sounded like a Recto. And if I want that I’ll just play the Recto.
Solidstate power amp and guitar cab was then the best fit for me. I can use the full amp models (no need to disable power amp sims for some/all amps), no weird eq to make up for the shortcomings or whatever power amp I’m using, and no need to mess around with impulses.
I don’t have an axe FX iii, but I have a II, and the most recent (and last) firmware update included some of the new ‘breakthroughs’ from the iii that have greatly improved the feel. Comparing it to my tube amps I don’t really feel it’s lacking anything now, as I did in the past. Though maybe my feelings will change in the coming months if I start noticing more about the sounds.
Personally I’ve never really been a big fan of the overdrive pedal models in the axe FX ii, so I still have a few real boost pedals on a pedalboard I plug into whatever amp I’m using (including the axe FX). The III has had all the boosts reworked though so maybe they sound good now.
One thing I’ll say is if you’re used to amps and new to modelers, it’s gonna feel like driving a spaceship at first. There’s a learning curve to setting up patches, tweaking things, etc. There’s also the requirement of self control to avoid trying to use every amp model, or trying to use too many effects, or mess with too many advanced parameters that you can’t do in real life. I was 100% axe FX for a long time before I got some amps and now I can use whichever I prefer at any given time. It was a totally different workflow since I was used to messing with advanced settings or dropping EQ’s wherever, which I can’t do in real life with a tube amp. Kind of a reverse if going from amps to axe FX, just gotta try not to be overwhelmed.