The only XD I chose over a Glock is the new XD-S. Saw it, held it and had to have it. Much smaller than my G36 which I had just purchased a few days before I got the XD-S. It is actually the only XD I have for the moment..but have had many in the past. I will have more soon though.
I like my G21 just fine, no complaints at all. It's set up with a Viridian X5L that fits it perfectly, and is factory black. Works fine as a night gun at home, & for outside when I walk the property. The XDM is just a couple ounces lighter, no laser/taclite, and is narrower in the slide. It makes a nice carry gun that way, so that's what I take when I go out. They both shoot great, I just use them for different chores.
I chose the XD SC over the glock because of the grip angle, the safeties, but the reliability/failures of the Glock was the key issue. I have 6,000 plus rounds down the pipe of my XD without a failure of any kind.
I never cared for Glock-I like the looks & feel of an XD period.I got an XD Service a couple of months after my wife bought herself an XD .40 SC. I sent it Springer Precision and had the grip cut down to except SC mags.I'm happy!
A buddy of mine wanted to try out some 40 cal subcompacts. We went to my range and rented a Glock (don't remember the number). We both tried it. We both hated it. Each shot stung like whacking a concrete parking lot with a baseball bat. After 5 rounds my wrist was numb up to the elbow. I'm not a Glock-hater, but that particular gun was just painful.
We took the Glock back to the counter and rented the XDSC 40 cal. That had plenty of recoil also, but it didn't hurt like the Glock did. I think he decided to move up to the Compact size and he's still trying guns before buying.
I just don't like the grips on a Glock. They are great guns and very reliable, but feel funny in my hands. I have a G20SF that I shoot OK, but it never feels as good as the grip angle on a 1911,XD,FN,SR9, or M&P.
Had a Glock. Had an XD9-SC. Now have an XDM45 4.5". XD/XDM is better for me because:
Grip safety, where Glock has no safety (no matter what they claim).
Loaded chamber indicator is MUCH more obvious than Glock's.
Cocked striker indicator.
Looks better, although this is not a deal maker/breaker
All that said, if the Glock 38 were a .45ACP instead of .45GAP, I'd be on that in a minute and get a 3rd party thumb safety. Glock's mid size pistols are tops. G19, G23, G32, G38--very light, longer grip than the subcompacts, 4" barrels, easy to conceal. I wish SA had that size pistol. Like most mfrs, SA's compacts have too little grip and too little mag capacity for me.
But I do not believe that Glock have kept pace with the marketplace.
Here's what I mean:
Plastic sights vs metal sights
decent backstrap system
decent slide serrations/grippiness.
Removable backstraps. (not til Gen 4)
Grip angle. (oh I said that )
Texturing that doesn't rip skin off
Stainless steel slide
Loaded chamber indicator or hole
Cocked striker indicator
stainless steel sub-chassis
beefed up spring box (what Glock calls a guide ring)
robust MIM extractor
frame rails incorporated into the steel sear housing & locking blocks
revolver-like trigger shape
second spring in the striker assembly (striker return spring, like is used in the 99 series)
the stainless steel guide rod
replaceable grip inserts that allow adjustment of both the backstrap and the palm swell dimension
Now I wouldn't want all of those - but some are very nice indeed.
Glock USA told Glock Austria YEARS ago (when the P99 came out, and the P2000) this should be upgraded on the Glocks as soon as they could.
Glock Austria, as most German/Austrians do, insisted they knew better, i.e you'll take what we make as it is perfect.
They lost enough $$$$ over the M&P and XDm & other polymer guns which had these features suddenly the Glock Perfection became Glock Perfection version 4.0.
Glock Perfection version 4.0 solved very few of the problems.
I owned a Glock, have for a dozen years.
Doesn't mean the company always knows what it's doing.
IMHO M&P and XDm surpassed them because it gave customers what they wanted in a reliable package without costing $700.