I do the vast majority of my demos with a kemper - i've profiled most of the nice amps i've owned over the years, and it works great. For most of my band's actual recordings in a studio, I still use real amps, but if I needed a random tone for a specific thing I wouldn't hesitate to use the kemper for it.
It's not a replacement for an actual amp, but if you use it for what it's intended for they are excellent. The effects are really nice, too. There's a whole bunch of great uses for it - they are a great tool for quiet recording or woodshedding, and anyone who tells you different is retarded.
Yes, the whole "digital is better than amps" people are stupid as fuck - it put me off trying modelers just like it put off a ton of others. In the end, they are non-overlapping magisteria to a certain degree; if we didn't have amps to model, the modelers would be useless bricks.
This fuckin unit is bananas…. Damn…. Plus the profiles he has installed are crazy. Some rare birds on here…. Thing has more death in it than a graveyard