I vote for the XD, I like the trigger better, grip angle, and from the ones I have owned ( XD40 and XDm40 ) ( Glock 22 and Glock 27 ) the XD's were slightly more accurate in my hands and off the bench. As far as track records, the XD has been around for years and is every bit as reliable. I also sold my Glock 40's due to excess case bulging to the point most once fired brass had to be junked. Full chamber support does make a difference, at least in the 40S&W round it does. I got 2000 once fired brass ( speer and remington ) from a local police dept., only 500 were reloadable and many of those were borderline due to bulging. Google (40S&W full chamber support) and see what comes up. The Glock 9mm's due not seem to be an issue though I have never owned a Glock 9mm.
As far as aftermarket parts, the XD may not have the variety of the Glock, but its getting better all the time. I would not limit my decision to just Glock and XD, there are many other well designed reliable semi's that are reasonable. CZ makes a heck of a gun at a reasonable price and don't overlook the S&W line, one of my carry guns is a SW99 in 40S&W, deadly accurate and 100% reliable, they also come in 9mm and 45. I would steer clear of the 45 though, I had one and the recoil spring wore 1/4 way through after a couple hundred rounds. I think S&W got a little aggresive in marketing as to my knowledge Walther never made the gun in 45acp and I think thats why, not enough room for the barrel and spring in the frame.