I have both. My opinion. Both are great pistols. I give the quality edge to Ruger. But if you are into working on your pistol, like changing barrels, or working on trigger, I would certainly recommend the Smith. The nice thing about the M&P is you can buy the 40, and get barrels for 357 sig, and 9mm.
If you want an out of the box reliable shooter, the Ruger is hard to beat.
Both like stated, are fine American made pistols. Which is a high priority for me.
To give you guys a chance to pick on the new guy. I did buy a Springfield XD tactical, giving no thought that they may not be made in the USA. So for now I pretend Croatia is a city in Illinois.