I prefer it to the one previous. playlists don't hang out on the bottom of your browser window (even when collapsed), they made all the buttons n stuff flat, they changed the position of the titles so that they can't get lost in the background should the ad du jour happen to be black (or white, because sometimes the titles are written in white) and I like the red highlights.
Don't like how the related videos stream seems to be entirely based on your search/viewing history rather than the specific video you are watching though. I see people complaining about the main page layout or whatever, but I never use that so it's whatevz 2 me.
Also seems silly to have the video window be off-center slightly, just to accommodate a slide in menu that you probably won't be using while actually watching something (rather than after a video is finished, or while a video is loading).