IF I was to OC, I would use a Raven Concealment holster. They are quality made, and they look Bad Ass too!
I carry my blackhawk serpa, usually on the belt not the paddle. It is a level 2. Lately it has been getting bad rep but I still like it and haven't had a single issue. You could always look into safariland holsters which are pretty nice. Find something comfortable is the best option. Retention isn't mandatory btw, but I still like to have it.