Nothing!

M&Ps do have a better trigger out of the box than do Sigmas, SDs, and SDVEs. The grip (back strap) is adjustable on M&Ps, while it isn't on these other models. I don't like the plastic recoil guide rod assembly, but I replaced that with a stainless steel guide rod assembly from Galloway Precision. I replaced the plastic rear sight with a steel rear sight from a M&P. I also replaced the take down lever with an extended take down lever. The only thing I don't care for on the SDVE is the slide stop...it does seem flimsy and cheap, compared to the M&P line.

None of these changes I made make the gun any more reliable...they were personal preference. The SDVE pistols are very reliable, and solid shooters. The main issue is, can YOU manage it? If you can't manage the trigger (and personally, I don't believe in modifying the trigger/fire control group) and some cannot, then it's not the gun for you. You may be able to manage the M&P trigger better...and if so, then that's the gun for you, or any other pistol that you can shoot effectively.

The gun itself is reliable...but it you and the gun are just not a match, for whatever reason, then it's not a good gun for you.