Sony clearly hasn't hired any UI people yet. The search feature is so bad that I'm still wondering if I'm using it right. Right now all I can do is go to the first letter in a title then scroll through every title (both games and movies) that PSN stocks to find what I'm looking for. If there's a proper search, I can't easily find it. So search is either useless or the UI is broken.
If you're lucky enough to find what you want then be prepared to do a lot more clicking to actually buy something. I'd say that it's at least double the clicks to actually download an item compared to the old store. The one thing I will give it is that the look is better than the old store, but the functionality is much, much worse. One star.