I have a Razer Onza Pro, Mad Catz MLG Pro, and Razer Sabertooth Pro.
I had to return my first Onza because of trigger issues, and after some time I just decided I didn't like it with the extra bumpers and such. This is when I got the MLG Pro Circuit. I do like that I can change out the thumbsticks, and this is probably the best controller available for customization if you prefer different layouts for the d-pad and thumb sticks. I even bought some of the increased resistance thumbsticks for it which were very nice for racing games.
Then I got an email from Razer about the Sabretooth, and despite a little reluctance because of my experience with the Onza, I felt like this controller was addressing the issues that I had with their previous effort. It is by far the best 360 controller I have used, and I have used it non-stop since it was available.
I would personally suggest either the MLG Pro Circuit or the Sabretooth if you want to try a premium controller. The Onza is now being used for PC games/emulators.