I own a SERPA CQC level 2 auto-locking holster for my XD's. They are awesome and I'll stick with them for my OC holster of choice, hands-down.
The unlocking/drawing motion is so smooth and natural (trigger finger), it's just perfect.
Blackhawk has a great product. And they stand behind it, too. I had a little issue w/ "rattle" of the gun inside it. I emailed them, and they sent me a new locking spring piece right away.
They get two thumbs up from me,for service and product and quality and price.