Like they said before this, all three manufacturers have solid reputations. In addition to mxxkffg's suggestion of seeing how they fit in your hand, see how comfortable they are to carry. I have a glock, and carrying it IWB is not comfortable for me because of its width. My buddy has an M&P, which is a little thinner and more comfortable to carry IWB.(assuming you plan to EDC since its sub comp). Good luck on your decision
I am looking at purchasing a new sub compact in 9mm. I was wondering what peoples opinions are of the three manufactures listed.
Well, you said sub-compact in the 9mm.
M&P makes a compact, not a sub-compact.
XD, I've no idea, and don't care to buy one anyway.
Glock makes a sub-compact. A Glock 26. And I love mine.
You should go Glock