I guess it depends on what you want...the Mark 23 is a big, heavy, specialized gun. Holster choice is limited to tactical drop-leg stuff. The USP Tactical is a great all around pistol, suitable for IDPA, etc. I've got a friend who shoots one. Pick one that suits your style. But, IMHO the Mark 23 is overbuilt, and overpriced, for a civilian user. Unless you just have to have a "SOCOM" pistol. But then I'd want the suppressor and aiming module, too.