Well, this thread came back once. I might as well bump it again.
I have a Glock 20 and a Stainless Delta Elite Gold Cup. Which one I would recommend would depend on what you're going to do with it. I got the Glock first, along with a 6" Storm Lake barrel, a Lone Wolf 3.5lb connector, a Mako scope mount, and a few other things with Pig hunting in mind. It quickly became my favorite all around utility gun. I carry it for a sidearm while hunting now, instead of my .45 Colt revolver. The Delta I got because I could; worked a swap with a friend who had it and found another identical with a serial number he wanted.
The Glock excels as a utility gun, easily able to switch barrels and the scope mount, mags are easily found and relatively cheap to say nothing of the 15+1 rounds available. It also isn't fussy about ammo, except that to shoot lead bullets you have to get an aftermarket barrel. But the Delta's trigger is
way better, and it'll shoot lead with its original barrel if you use mild loads. It is fussier with ammo; it doesn't like the American Eagle load, for example.
If I could only have one, I'd probably stick with the 20 for all-around usefulness. A friend has a 29, but it's harder to find accessories for so unless you're planning on using it as a carry gun I'd stick with the 20. But I'm really glad I don't have to choose!