Well, right now 9mm is expensive, if you can even find it. I got the XDM 5.25 in 9mm, as I wanted something to shoot for fun, and possibly USPSA, without the cost of .40 or 45acp ammo. The 10mm XDM 5.25 had not come out yet at that point, but even if it had been around, 10mm ammo is on up there...