My carry pistol is a S&W M&P40. I had both the full size and the compact and ended up selling the compact as there was no noticable difference to me for concealed carry. Plus the full size had the extra couple of ounces forward that made the gun more controllable. But IMO you should find a handgun that fits you. If you're accurate with it the target on the other end won't know if it was hit by a 9mm or a 40.