XD is not a better weapon. It is also not a worse weapon.
I prefer Glocks in 9mm
I prefer the XD in 45 acp (grip size)
Probably would prefer Glocks in any other caliber... or even another gun maker.
Does anybody actually use the XD holster? The mag holders I could see. And Glock also gives you a loader device so the Free stuff is nice but...I doubt the cost of that stuff is enough to determine the desire to purchase.
Glock has become not only the name in polymer pistols but in handguns in general. Glock is always the standard other guns are measured by. Glock is the kleenex of tissues. Say XD and most non gun people would say what? Say Glock and they know what you are speaking of.
Even this thread shows that, why not XD vs other Polymer? Why not XD vs HK or Sig or M&P? Nope Glock got used.
The Glock 19/23 size guns are hard to beat for size, capacity, weight and overall usefullness, concealable but full size. And the Glock aftermarket and support product market is vast.
Walk in to a gunshow with an XD box and a Glock box and see which one gets the most attention. The "what have you got to sell question" will change to "what kind of Glock are you selling."
Every Gunshop sells Glocks, at every gunshow Glock usually has at least 1 booth dedicated to it, for parts, (never seen an XD or Sig or HK or Beretta Booth) and Glock's marketing is second to none...shirts, pens, backpacks, shooters stuff posters, waterbottles and lots more ( I know many other companies have some of this stuff to but they don't hawk it or get it out in front like Glock does).
Glock aggressivly goes after police contracts and sticks with less than popular calibers (10mm, 357 Sig and even the 45 GAP - which won't die if Glock continues to support it) 10mm fans owe Glock bigtime.
Does all this make the Glock better? Who knows, but it does make them a company who will be difficult to unseat and thus better in the business aspect of gunmaking.
Which gun is better = the indivdual shooter will have to decided. And the shooting public will determine market share.