It's amazing how much of a heated debate people get into over the Axe-FX. And it varies from forum to forum as well. It seems like the recording forums are full of people who balk at the price or try to say that it can't sound as good as a tube amp, whereas the forums for true afficianados of guitar gear seem to give the Axe-FX a lot more love.
Many of us who have gone the Axe-FX route end up selling more in amps and pedals/FX than we spent on the Axe-FX, which really makes the cost much less of an issue. And even if you don't factor that in, I feel that the Axe-FX is worth it. I started with an Ultra and ended up selling that when the II was announced because I wanted to stay cutting edge. In the time I was on the waitlist for the II I tried to get by with the software plugins, but they just didn't cut it
for me. Even at the lowest latency they didn't have the feel of the Axe-FX and the sound wasn't there either. (I wish I could sell the plugins now and get anything near the resale value I got from my Ultra, LOL.) I really hoped that they would work for me, but when my number came up on the list I was happy to get the Axe-FX II.
Haven't tried the Kemper, but amp matching really doesn't interest me very much. (I've used the matching features in the Axe-FX and while nice, I've gone back to turning knobs to get the sound I want.) I have heard it's very nice and on many of the guitar forums it is ranked up there with the Axe-FX. It seems to be more along the lines of which workflow you prefer as to which you like better.