I own both.
No contest the S&W M&P.
I liked the XDm9mm. Put one of the trigger kits in it and shot it in my clubs weekly steel matches. Doing well and I like the gun.
Started having jams, no problem, it was time to replace the magazine springs. DUH! none exist. Springfield doesn't have them, and to this day I don't believe they do have them. MecGar makes the magazines but will not sell them, Wolf doesn't make them.
I could buy a magazine rebuild kit, for 18 to 21 dollars per mag. I owned 12. I could not find springs until a year or so ago, from one of the better XD/XDm support houses.
Then a friend of mine had his extractor in one of the XD compact 9mm go south. No problem, we call for the part. Springfield will not send it. He had to send his gun to Springfield.
And as far as I know, I no longer follow the XD/XDm family, they still are having issues with the Striker retainer pin too. I am done.
To me that is examples of a manufacturer/reseller refusing to support their own guns. If I can't get parts in a practical manner it's toast. I gave it to my Son in law.
M&P's I have had 4. Traded the compact which I had placed the Pro shop sear I got in the Pro9 for a full size 45. So now I have a Pro9 which I run in the weekly matches for almost two years now, and love it. A full size 9 and the full size 45acp. All of them have APEX kits. The Pro9 is a competition kit, and the others are carry kits. Great triggers.
No contest. parts are available from S&W, the Pro9, an early one had the striker break. Called and they sent one out, no charge of course. While waiting I had taken the striker out of the compact an put it in the Pro9, and put the new one sent by S&W in the Compact. Zero down time.
I replaced the rear sight on the pro with a Warren Tactical. Love that wide rounded sight with the original front fiber optic in green, which I see a lot better. Love the gun.
My Glocks have never quite fit me right. I have often had problems with Glock magazines going back to the late 80's and as recent as 3 years ago, that a brand new Glock 19, the two included magazines, neither one worked properly. I fixed them after parts were sent from Glock.
I do like the HK P30. I got 3 of them and a P30L all of them with the LEM trigger. I did shorten the slide locks on both sides of all of them. They really run nice now.
If the reset is important to you, don't get the HK. I learned to shoot in an era that reset was not an issue, and to me still isn't. I am a proud trigger slapper.
good luck.
Fred