The XD-9 SC over the Glock 26. Here's why:
(1) Much better grip angle and ergonomics than the 26
(2) Grip safety
(3) Striker status indicator, both visual and tactile
(4) Ambi magazine release (especially nice if you're having to shoot weak hand)
(5) Loaded chamber indicator, both visual and tactile
(6) Comes with both a 10 and 16 round magazine -- your choice.
(7) Lifetime warranty
1 - That's very subjective. There are many people who like the Glock's grip and dislike the XD's.
2 - What real use is a grip safety on a gun with a long trigger pull? I can see it on a 1911 but not otherwise. Most AD's occur during holstering, and a grip safety offers no protection in that scenario.
3- All Glocks have an inherent striker indicator. If the trigger is forward the striker is cocked. No need for any other silly indicators.
4 - I'll give the XD bit of credit here.
5- LCI has been standard on Glocks for quite a while now, although I see no need and have no use for it.
6- There are numerous size Glock mags, including 10, 17, and more rounds. They're cheap too.
7 - Glock doesn't advertise lifetime warranty, but if you read the reports from customers you'll find they almost always "do the right thing". Glock's customer support is excellent. By the way, aside from a cracked frame, Glocks are so simple and afermarket parts so numerous that you can repair or improve any aspect yourself.
Bottom line - advantage Glock - much more mature design than the XD, much better aftermarket support, and a proven reliability record beyond question.