I have an XD40 service and a XD9SC. The 9mm, IMO, is definitely easier to shoot, even with the shorter barrel. The .40 is snappier than the 9mm, but is still manageable. If you're new to shooting, then my recommendation is the 9mm. Ammo runs about $10 less per 100 for the 9mm than the .40, so you'll be able to get more practice time, assuming you're like the rest of us and don't have an unlimited shooting budget.