Well. I should hold this one up, since it's from a German develpoper, but ... well, there's a lot of problems. Most notably that you don't grasp the metrics, as the stats - especially for weapons and armor - are quite extensive, but don't actually tell you what they really do. The worst imbalances have been ironed out with the latest patches; still there are clear paths of "easy going" and "rough ride".
If you like action RPGs, this is still a solid contender with all the usual stuff, but - and I say that as a NON-fan of Diablo - it's _not_ anywhere near that league, as it lacks a lot of polish. It does put aside horrible contenders like Loki single-handed, though. 3 Stars from me.