I just sold my Axe FXII last week because the Kemper has superior tone and thats what is most important to me. The Axe felt too digital and while really good, it just didnt deliver me that authentic amp tone. I tried for about a month of playing the Kemper and Axe II back and forth to see if I should keep the Kemper or the AxeII. I decided to keep both, but I soon realized that when I played the Axe the tone just want there compared to what I was getting out of the Kemper and so I decided to go 100% Kemper and part with my AxeFxII.
If you prefer authentic powerful in your face tone with simple plug and play then you want Kemper. If you are the type who likes to tweak endless amounts of parameters in search of a good sound then the Axe might be for you. One thing the Axe does have alot of is great effects but the Kemper has the basics covered and more are on the way. That was actually the only reason I was going to keep my Axe. But even the cool effects werent enough to draw me away from my Kemper.
As for plug and play, the first day I got it, I took it outta the box. Plugged in my guitar and headphones and was taken to a new world I never knew could exist in the world of guitar processors.

I seriously was shocked at how great it sounded right off the bat. I didnt get that feeling when I first plugged into the AxeFxII.
Like you I dont have any amps to profile. I am all about hi-gain metal! The kemper SLAYS the Axe Fx in this regard. Diezels, Engls, oh man there are some incredible Engls in the exchange! Look for a user called JUANMA BLANCO. He has 82 insane incredible profiles of various amps. Get them all and prepare to have your face melted!
Good luck with whatever you decide!