I felt ripped after playing Diablo 3 for a few hours. I purchase SC II and had a really good time, but it was "more of the same". It felt like a remake of SC with a different campaign and more units. The basic gameplay mechanics were the same. Still, it was well made and fun.
Diablo 3 is simply boring. Having to be online to play single player is mindboggling stupid, character customization is very limited in comparison with it's predecessor, and the loot is usually crappy. The gameplay changes felt like Diablo for dummies. And don't get me started on character design and enviroments, they don't felt like you're playing a Diablo game at all, more like a clone.