Thought I'd revive this string since it is a good one (and I'm largely responsible for side-tracking it this winter).
I prefer leather over Kydex--even when shooting IDPA. Truth be told, if I was fast and accurate enough to be concerned about the fraction of a second gained in wearing Kydex, I'd probably use it. I have an Uncle Mike's paddle/Kydex, but came to realize that I would not wear it on the street and felt it went against the spirit of IDPA to wear it to a match.
I currently use an El Paso Saddlery #77 Tortilla holster. This model has a thumb break, a reflection of the protection against loss I wanted given occasional horseback carry and other back-country forays. El Paso also makes a #88 Street Combat model, that does not have the thumb break. I'd like to have one of these as well.
I went with El Paso after reading a revue from Jim Wilson in Shooting Times, a writer I respect a lot. I highly recommend El Paso holsters after owning one for a couple years now and would encourage any of you looking at new leather to check out their line.