Until recently I had an XD9 bi-tone. In many ways it had seemed the perfect plastic pistol for me in that it felt good in the hand, had a lefty friendly mag catch, pointed well, functioned flawlessly for over 1000 rounds, et cetera.
Well, I am getting a Beretta PX4 to replace it after firing a friend's. What I found I didn't like about the XD9 was the length of pull between the grip and the trigger and there wasn't anything I could do about it. The Beretta instantly made me fall out of love with the XD9. I have long fingers and the trigger's proximity to the grip on the XD made me contort my trigger finger slightly, which adversely affected my accuracy with the pistol. The XD turned out to be just another exercise in "one size fits most," and most is not me unfortunately.
The new Beretta with the large backstrap allowed me to perform drastically better with it than the XD9, even with the old DA/SA transition.
If the XD9 truly fits your paw, buy it. If you find that you have to alter your grip or your triggering to fire it, for having a hand either too small or too large, do yourself a favor and get something that features adjustable backstraps like the Beretta, HK P2000 or Walther P99. If you want an American one S&W makes a few too.