I've been really happy with the KR8, but I will say that the experience is heightened a *LOT* with the right cartomizers. The "generic" (hard cap) type just don't cut it for me. I've tried several types from several suppliers, but the Gold Label cartos from CigEasy are by far the best in my opinion.
That said, the KR8 is a really great device for those who just want "simple, but effective". Easy to refill, easy to maintain...I suppose the main determining factor in whether or not you would like them would be the device you're using currently. If you've already got something like an Ego, the KR8 may be a downgrade.