Here's a different question to ask yourself-

what are the best shooters in the world (or the world you care about) shooting? I look at USPSA and IPSC.
-I believe there's a reason why so few people at the top shoot XD's- because it's harder to win with them. They have a VERY terrible slide weight and height over bore which translates into harder to manage recoil in any caliber to caliber comparison with most other models. HK is guilty of this too, IMO.

I look to the top competitor's choices to start my search. Out of those guns present (a shitload of glocks, M&Ps, and 1911s in extreme customized format) I look at what are in use by LE and MIL communities (much less at mil because pistol is not their game...)

Next, I look at what's got the best rep for reliability.

In in my reasoning I was left with Glock and M&P.

Glock aftermarket trigger parts parts abound and most are less than $50
M&P has the APEX trigger ~$150? Dunno- pricey.

If if you take both guns down you might think that the M&P is a slighly more complicated copy of the glock...

That's why I like my glocks. If I had to sell all but 1 pistol I would choose my g19 for everything every time.