The biggest problem for me is finding a holster to accommodate my choice of accessories. Once you find a backing that is comfortable and secure, 9 times out of 10 the manufacturer does not support your choice of light, laser and/or red dot. This is especially true of a new firearm offering. Who wants to wait a year or more to carry your favorite mini blaster?
I settled on the AG IWB Cloak Tuck as the most comfortable backing for me but had to go to White Hat Holsters (local for me in Mansfield, TX) for the custom shell to accommodate the red dots and Surefire XSC lights on my OSP and RDP models. In the winter, I carry this setup with the shirt tucked in behind the holster and a jacket over it. When I am wearing a suit jacket, I carry a full size frame gun with light/laser/red dot and OWB. The object is to keep only one layer of clothing over the pistol.