For the record, my gun is carried without a bullet in the pipe (unless walking in the woods) and does have a manual safety. I keep one out of the pipe for my own piece of mind.
Carrying an empty pistol puts you at a severe disadvantage for using it. As does a manual safety. A manual safety is only required on a very few designs, the M&P is not one of them.
An empty pistol takes two hands (or some gymnastics) to load. Carrying it in this condition is just foolish. The pistol will fire only when you pull the trigger. Full loaded in your holster it ain't doing anything by itself. If you're comfortable "in the woods" what's the difference on the street?
Mr. Murphy will always find a way to put your pistol on SAFE even if you didn't. This means you must always take the pistol off safe every time you shoot it or it'll just go click. This is easy with the M1911 where the current training doctrine places the firing hand thumb on top of the safety lock all the time. All the time. Low ready and safed? Thumb is on top. Shooting? Thumb remains on top. This ensures the pistol will fire every time. The M&P safety does not lend itself to this mode but you gotta check it. Fortunately you can remove the M&P manual safety easily the next time you detail clean the pistol.
My M&P9 has a 4-1/2 pound (Burwell) trigger pull just like my M1911s. I doubt I'd want a lighter trigger.
If you're going to continue to carry a pistol with a safety (on or off safe) -- or, worse, an unloaded pistol -- find some time and a range and do your own Tueller Drills and determine your decision distance.
21 feet is the normal extreme danger zone. Within that zone the typical
well trained shooter will be unable to get the pistol out of the holster, fire, and hit before the attacker is upon him with a weapon such as a knife, baseball bat, etc. If you're dicking with loading the pistol or fumbling with a safety I'm betting your danger zone will be much greater. This is a sucker bet, so don't take it!
-- Chuck