I mostly use skateboard tape, as its slightly less abrasive and aggressive, with a finer grit than the skid tape. Its also about half the cost, about $6 for a 9" x 34" sheet vs about $10 a roll for a 2" x 15' skid tape. You also get more size and shape options than you will from the skid tape rolls.
I use it mostly on the front straps of my pistols, but on my Glocks I use it on the side panels, and other places on other guns, depending on the gun. I also use it on all my guns, not just the pistols.
I saw those gun specific decals and ordered one for the Glocks. I figured I'd at least get a pattern for the others if nothing else. They are somewhat generic as to fit, and I was better off with what I had done already, as it was basically a custom fit for me. For what you get with one sheet of skateboard tape at about 1/2 the price, you can screw up to your hearts content, and still be ahead. If you dont screw up to bad, you can do probably every gun in your house for $6 and still have plenty left over.