I didn't try the app (because of silverlight) but I really like the design. Is black the new blue?
Of course this is of no matter to the end user, but where it does have impact is that hopefully I was then able to spend more time working on features that add value to the application, thus benefitting the end user.
There's also some area of the application (like commenting on videos) which would have been really hard to develop using just javascript.
In terms of the design there's definetely been a trend towards darker colours. I love the style that Adobe have used for products like Photoshop Express and this was definetely an inspiration.
Thanks!
Working with tools with which you're the best makes great applications... as long as you keep updating your toolbox.