I have the Axe-Fx and I've used all modelers on the market. Revalver is a fine piece of software, no doubt about that. Soundwise I can't tell which one's the best of those two. It's the hardware that's the problem. A great DI, a nice fast sound card, a computer that can compute and so on. I'm tired of all the stuff that has to be perfectly compatible to be able to get what I want: plug and play. The Axe-FX has a total latency (AD/DA) of 1 ms. With plenty of effects, it could go higher but never above 2 ms. It just feels right. I use it everyday, when I'm opening projects, opening songs in the DAW, copying files, making backups...you name it. Plug and play. It starts within a second and it has everything and more when it comes to effects. Custom IR's too, of course.
Oh yeah, there's no problem whatsoever to get a fantastic metal sound.
Get the Axe and try it. You've got 15 days to try it and send it back if you don't like it. if you miss the refund deadline, just sell it to anyone of those hundred people that's waiting to get their hands on one.
Good luck.