I've tried a number of IWB holsters. At first I liked the kind that clip on over the belt, and they are convenient, but the clip will gradually chew up your shirt tail when you sit in a car seat. It will be perforated with little holes.
The best made, most comfortable IWB I've found, and the one I swear by now, is the
Milt Sparks Versa Max 2. I've also got their Summer Special, which looks like it would be even better for its simplicity, but the VM2 is the one that cannot be beat. It ain't cheap, but it will last a lifetime, and is the most comfortable and efficient of all I've tried.
Get the horse hide. Tougher, slicker for an easier draw, and moisture resistant.