Happened again. Went to the range this morning and shot 100 rounds. Experienced 2 failures to extract. So, 4-5 failures to extract in the first 350 rounds before I sent it back to S&W where they replaced the extractor.
Since it has been back, I've experienced 3 failures in 450 rounds.
I can send it back, and be without the pistol for 4 weeks and hope they fix it this time. Or, I can sell it at the pawn shop and be done with this pistol. I'm definitely leaning toward ditching it.
Aargh. I feel your pain. My 1.0 Shield 9 suffered from similar FTE problems. I sent it back to S&W, and it was returned unrepaired as they determined that everything was OK. The FTEs continued. Around 5,000 rounds, I'd had 27 FTEs and 4 failures to feed. At that point I decided that while having failures at the range was annoying, I could live with them. What I couldn't live with was having a single failure with self-defense ammo. I then began to test various brands of high quality SD rounds to see if I could find one that functioned 100% in this ammo-picky Shield. I set a high standard: a round would have to fire perfectly a minimum of 200 consecutive times before I would consider carrying it.
After shooting many rounds of many brands (kind of fun, actually), I discovered two SD rounds that function perfectly with my Shield. The first is Hornady Critical Duty 135g +P. To date, I have shot 362 of these with no failures, and these are what I carry. The other perfect SD round is Federal HST 147g. To date, I have shot 225 of these with no failures. It's always good to have a backup round. And to demonstrate how ammo-picky my Shield is, it absolutely choked on HST 147's cousin, HST 124g +P.
Bottom line: Try different brands of ammo, concentrating on those all-important self-defense rounds that absolutely must function perfectly. I'll bet you can find at least one.
As to the claim that M&P extractors are junk and should immediately be replaced by Apex as soon as possible, that has not been my experience. I have two other M&P semi-autos, a 1.0 40 compact, and a Shield 45. They have nearly 21,000 rounds (yes, twenty-one thousand) between them with exactly 1 (one) FTE. Even with my cranky Shield 9, I suspect that the culprit is not the extractor, but a wobbly ejector. I pointed this out to S&W when it was sent back, and they said the the wobble was within spec.


If you otherwise like your M&P, try experimenting with different brands of ammo, emphasizing the all-important self-defense rounds. It's educational and fun.
Good Luck!