If you are sold on Plastic, I really like the Fobus Paddle for my HK usp compact. It holds the gun tighter to my side than did my UM Kydex Paddle. I have tried the blade-tech injection molded kydex for my 1911, but it lacks cant, and is too long for me to conceal under a t-shirt.
With the fobus, you're only out $20 if you decide you don't like it.
Hope that helps a bit.
--usp_fan