Dog,
If you prefer the M&P, stick with your M&P.
For many years, people pushed Ruger to build a 1911.
In a world where there was a bucket full of 1911 makers, domestic & foreign.
When Ruger did, theirs wasn't anything groundbreaking, or anything "better" than what most other makers were putting out, but those are still selling for the company.
My American sample's on the way, so have not handled it yet.
I have looked all over YouTube (not as THE definitive answer, but for initial research on what others are saying) & found a T&E that was quite abusive. The pistol did well.
The features are sound, the pistol has what I call a pro-grade set-up as far as I can see so far, it is a step forward for Ruger, and time will tell us more than non-hands-on Internet gun forum chatter on a gun not even really in circulation yet.
Just put it in perspective.
It's kinda like the photography world, where you have "consumer" grade & "professional" grade.
$90 consumer grade point & shoot pocket cameras offer convenience & a "good enough" picture for a major market share among those who want to save vacation memories & post Facebook stuff. And not spend much money.
If you want better resolution, more features, a longer life, and more capability for a better end-quality result, you squeeze your wallet hard & buy professional grade cameras at ten times the price.
While the price analogy doesn't apply as directly to the SR9 & the American, the rest does.
Materials-wise, with a plastic frame Ruger loses no points where that's what the market is buying.
Cast-wise, today a non-issue since Ruger's done quite well with their cast parts for several decades, they're hardly alone in using castings, and I don't even know if the American has any yet.
If it does, and the pistol was designed with military acceptance criteria in mind, I wouldn't worry about cast parts.
MIMs? EVERBODY's using MIMs.
And I'd say this pistol is a clear indication that Ruger IS improving its offerings.
It may sell, it may tank.
We'll see.
If you don't want one, don't buy one.
Denis