Well I would say that i am qualified to write an opinion on the matter, because i own both, an xd and Glock. so i will give you what i think!
i have a glock 19,
with safari land leather paddle holster
3.5lb disconnect
extended slide release
xs 24/7 big dot sights
and an xd 4" service model in .40!
Fobus roto holster
couple extra mags
pretty much stock!
pro's of xd............
1) i personally prefer the three dot combat sights to the glocks standard sights
2) the sights are metal on the xd and not on the Glock.
3) i prefer the grip angle on the xd, feels more natural and points better for me!
4) i really like the grip palm safety on the glock
5) the cocked indicator is a nice addition.
6) is a little cheaper in price
7) can use lead loads/ reloads in the xd.
8) and finally, i prefer the stock xd trigger to the glock trigger.
Pro's of the glock.
1) More calibers to choose from
2) more frame sizes ie.... single stack (glock 36)
3) less expensive magazines
4) I like the finger groves, it is a little easier to hold onto in wet weather.
5) tennifer finish is great and have had zero wear on the slide, holds up real well.
6) accessories out the ying-yang, they make everything you can think of, because they have been around for so long!
2000rds + in the xd, factory of all kinds, reloads etc!
600rds + in my glock , and 1000's in various other glocks,
i like the glock but for some reason i am still in love with the xd, maybe it will change but the xd is my favorite as of now!But with the upgrades to the glock that i have made it is a real fine line between the two. Hope this helps.