I don't own one but did also "fondle" one at the gun shop. After several reviews, not just the fluff marketing ones trying to hype sales some of the SR9's, they all mentioned the mag disconnect safety, and complex multi-part internals. Multi-parts can have a higher likelihood of problems, that the owner will never be able to repair unless a pro gunsmith. Here's one quote:
"Some are critical of another safety feature called a magazine disconnect safety. Unless a magazine is fully inserted into the pistol, the gun will not fire, regardless of whether or not the chamber is loaded. While the trigger will function and the gun can be dry-fired with the magazine out, the firing pin will not strike the primer without the magazine in place. This is not the first pistol to incorporate this safety design, and the only real drawback is that a chambered cartridge may not be fired without the magazine present. It is a safety feature engineered more towards novice shooters. Many modern firearms incorporate complex safety mechanisms, which, in my opinion, merely make the internals of the firearm more complex, leading to a greater chance of mechanical problems and more difficulty in service and repair."
http://www.firearmsfirst.com/?p=14I went ahead and bought an M+P, Ruger semi's have a love/hate relationship with owners, I kept my Ruger family with revolvers and 10/22's. Sometimes the design engineers forget what used to be the rule: "Keep it simple,,,stupid". If you can shoot one, test drive the hell out of it. Good shooting.
Just my .02cents.