I think this is great, though I found myself confused by why I can't drag emails from one inbox to another. (I have multiple inboxes enabled.) No biggie though, hopefully that will be rolled out later as well.
As much as I want to be a keyboard-snob, I find this feature to aid my productivity due to the sheer number of labels I have.
Hasn't happened on my screen yet.
Apparently they are rolling it out over a period of time. You should get it today though.