I have had extensive use of each weapon in both 9mm and 40sw. In compacts and regular service pistols. I currently own an XD 9mm and .40, both with the four inch barrels, and a really old G17.
Glocks
Luger angle grip, personally you need to hold each, and decide.
Like stated earlier, mag catch is sort of difficult, but certainly manageable.
Personally I love "ball in the bucket" sights, they just pick up well for me.
The only thing I don't like about Glocks is all the plastic, mags and certain parts just don't seem like they should be plastic. However, this glock I own now I beat around, and don't really clean. I like being mean to it, yet it still bangs away, and I haven't lost a hand yet.
XDs
1911 grip is very comfortable to me, but like I said hold both.
Stainless factory mags are awesome, but the springs need a little break in or get a mag loader.
3 dot sights are ok, not my favorite, but they get the job done.
Grip safety makes it difficult to discharge the weapon when your grip is not optimal, so grip it tight
In the .40s I do feel a little more muzzle rise in the XD, but with practice you can get the sights to come back down for an accurate double tap, (sorry must be P.C. "controlled pairs")
Also if your are an accessorizor, there is little out there, but it is getting better.
Blackhawk SERPA holsters are frickin awesome with XDs.
My XDs I baby not because they are fragile, but because I enjoy them. However, I just can't give up the different feel and look of the Glock, so I keep one for nostalgia.
Either way these two manufacters, have developed two decent firearms, each I would stake my life on.