I have not tried it. I've read people saying what you said, but almost invariably in the comments or responses, please say like 5 simple configuration changes to make it boot to and behave exactly like a normal desktop with the option to switch to metro.
Also that it's runs much faster, boot much faster, uses less resources, and has a nicer desktop
I have heard a few things regarding bugs, or annoying design decisions, but I think people don't give MS enough credit. If there's anything broken about it now, either in the form of a bug or a usability issue, I'm more than confident it will be fixed. I'm also confident that the finished product will be be better than windows 7, which is an awesome OS in my opinion. Also, I think the idea that the same applications will work on tablets and phones sounds amazing.