I don't like black/white icons at Finder side panel, colored ones from SL are way nicer.
It's basically brought everything in line with iTunes 9, much like SnowTunes did.
iTunes lost the coloured icons, and now the Finder has had the same treatment.
It looks "clinical", but one thing I do not like is the new Quick Look window.
It's gone from a nice black, semi-transparent interface to a grey window with a full screen button and option to open in Preview. Sure, it matches the rest of the OS, but I love opening a movie file in Snow Leopard and having the nice black, rounded corner window.
As for Launchpad, the whole thing seems like overkill. Sure, it looks gorgeous in terms of UI, but to open it you need to either click on a dock icon or a predetermined hot corner. By the time you do that, you could click on the icon for the actual app you want to launch!
Sure, Launchpad will be good for apps that aren't on the dock, but opening Launchpad and seeing the same set of icons on the screen AND on the dock is over the top in my opinion.