I'm starting to like it. I can see how its useful. No more double-clicks to resize a window. Plus, you can drag it back to the top and it will maximize. As mentioned, it is a bit touchy though. I accidentally dragged it to the top and it maximizes, but in my mind I didn't want it to maximize.
Users in a corp environment may need a class for these "features". Otherwise, their going to think, like I did initially, what the hell is it doing or what the hell's going on. And then support will get inundated with calls.