So i have spent the last few weeks tweaking my AXE FX non stop, i made about 6 patches that I'm really happy with. One clean, two rhythm (one power ball / one Mark IIC+) and two lead tones (FAS Lead 2 and 5150).
I originally found a Mesa 50/50 on craigslist for cheap and started using it with my presets. They sounded good but the power amp really "colored" the tone, meaning a lot of amps started to sounds similar.
Then i got an SLA 2 used for dirt cheap, i tweaked the presets a bit more and could really get a great tone, and more importantly a very authentic tube feel and sound. Its hard to explain but the same nuisances you get from different amps the AXE FX manages to replicate very well. I tested it out "live" with an ENGL Powerball / Mesa Dual Rec (90's) / and SLO100 / and even though the tones were not exactly identically the "feel" of the amp with the solid state power amp was more accurate than it was with the Mesa power amp.
Im still working on getting my patches perfect, and will have some videos recorded soon. But just my two cents in the tube vs solid state preference at this time. The point I am at right now I would say if you want more flexibility go with solid state, if you want to replicate a specific tone go with tube. For now i am going to be sticking with the SLA 2 and using the Mesa with my Pod XT.