No, but there's no one in my circle of friends/acquaintances that's actually bought one. I've got a friend who's been waiting 8 weeks for me to pop over and stick some extra RAM in his PC, despite my reassurances on how easy it is.

Of course I'd expect a MB to be properly tested and certified, but right now I'd only buy the Pi in a case of some kind with a pre-installed OS and some readily available apps. So to me it's substantially more geeky than a MB.