Works for me, but I'm a Windows Phone user, so slding up is natural for me. Had to play with it the first time, to get it, but after that, no problem. I think some will complain that it is difficult to do one handed. If you have trained yourself to hold your phone such that you can turn on and slide over with your thumb, I don't think you can slide up far enough to open the camera, unless you have some long fingers (thumb). Not a one handed user myself, so it isn't an issue.
it is interesting they found the rapid access to the camera, 'pioneered' by Windows Phone, important enough to emulate, and opted for a WPish slide up, complete with window bounce, to do it.