I love the fact that they chose to have a black background, I work usually during daylight hours so I watch videos at night, so watching videos with a bright white background in the middle of the night is a pain. So Vessels chose to use a black background is so much easier on the eyes. Yeah I know most people don't really care about that, but for me its a huge issue. I also like the way they have the videos setup, no links to random videos I dont care about thrown all over the screen and ever though the comment system seems a bit primitive and useless, its still better than the awful google+ youtube comments that aren't in any real order and make no sense.
Anyways love the new platform, hope it works out for you guys