See it with your own eyes
The written review for Thinkgeek's Pro Controller U (ugh I can't stand that name) detailed my issues with the controller, but I felt to really drive them home, a video needed to be created. They're the kind of problems that can be detailed in text, but seeing them in action just works so much better.
As you can tell from the video, the controller has a few hefty issues which make games pretty much unplayable. If I had to sum up the controller in a single word, it would definitely be "disappointing."