Well, I've had the MP40 about a month or so now and I've been able to sneak some rounds through it when the 2011 wasn't looking. I've gone through somewhere around 300-400 rounds of various ammo, both full power and the infamous "40 light", truncated cone and hollowpoint, jacketed and moly coated.
Not a single failure to fire that I can attribute to the pistol. I DID have one failure to fire last night, but that was a bad primer, and no fault of the gun. I haven't yet cleaned the gun or done anything to it, other than blacken out the two dots on the back sight. Word on the street is that Dawson will soon have a new front sight out for the MP, which I will purchase as quickly as I can. The stock one is simply too damn fat.
The MP40 shoots very very soft, is extremely ergonomic in the hand and I am overall very impressed with this pistol. I will likely shoot it until it jams, or until I just can't take the filth anymore, whichever comes first. As it stands now, it has almost made my minimum requirements of being able to shoot 500 rounds without cleaning. Right now I'm running a combination of FP10 oil, mixed with some heavy synthetic motorcycle oil - and a fairly light coating at that. Once the pistol gets properly broken in, I'll likely only run the FP10 through it.
As the pistol comes with 3 grip inserts (Small, Med., Lrg.), allowing you almost tailor fit the pistol to your hands, I put the large inserts in and it fits just about perfect. The stainless mags are awesome - they drop free quickly, and there's nothing in the mag well to mess you up as you're doing a speed reload.
The trigger is very good - for a plastic gun - with no spongy slack like you'll find in a Glock, and the trigger breaks remarkably clean for what it is. No, it's nothing as good as the trigger on my 2011 -
nor do I expect it to be. For a plastic gun, it's damn good and I won't be doing a thing to it, other than shoot it and dry fire - which will smooth the trigger out even more.
If the MP turns out to be dependable and reliable (word on the street is that several PDs have run 10,000 rounds through with no failures - so I see no reason to think it won't be...), then Smith has a serious and potent contender to the dominance that is
Glock.
The pistol has proven to be spot on accurate with my hand loads - keyholes and silver dollar sized groups of rapid fire at 10-15 yards are very (and easily) doable.
If you're a lefty, then Smith has really helped you out with this pistol - it comes standard with ambi slide releases, and you can easily change the mag release button to the other side of the pistol.
About the only downside at this time is that things like holsters and mag pouches are still a little hard to find, but can be found (I converted an Uncle Mike's kydex Glock 21 holster with very little effort) and the price of mags is pretty expensive, about $35-$40 per mag.
I'd be willing to bet that next year, once some of the "new gun" hubbub has died down, you can pick up an MP for under $400, which again, would put a serious crimp in Glock's style; and I expect that as time goes by, holsters will be readily available and the price of mags will come down as well.