holster choice
It depends on your build. I've always found IWB works better with a gun with a tapered slide contour. For full size guns, I always liked IWB carry with a Browning HP.
I have a Milt Sparks Summer Special holster that fits my Sig 230/Walther PPK/Kahr P9 and I carry that way in the summer sometimes. I also have a DeSantis IWB holster for the Kahr that a buddy gave me -- he originally used it for a Detonics he carried as an off duty gun 20 years ago, and we discovered that it also fit the P9.
I prefer a pancake type holster, even though I just lost 18 lbs . . . . I also really like some of the Kydex holsters that are available now. I have a bunch of Kydex holsters from Ky-tac and one from Mach2 Tactical and one from Comp-Tac for different guns, and they all work pretty well.
If you go IWB, be sure to order a couple of pairs of pants specifically dedicated to IWB carry, and get them with a waist size an inch or two bigger to accomodate the gun and holster.