I second the Milt Sparks Versa-max. It's the most comfortable IWB holster I've ever tried. Advantages are that the loops are offset, giving you a thinner profile and more stability. The Glocks are so bulky that you need all the help you can get. Also, the Versa-max is the most comfortable IWB rig I've ever tried ...... it has it's smooth-side out and gives you a wider bearing surface to spread out pressure from the firearm. Looking at the Side-armor model, it looks interesting, but try it for comfort and check the return policy. All the cool moldings could dig into your side after a couple of hours. The most comfortable IWB holsters will be smooth-side out, have plenty of bearing-surface, offset loops, with few or no protuberances sticking out against your side.
The Glock presents its own set of challenges for a tuckable design. I learned this the hard way years ago when I ordered a Mitch Rosen Workman, the first tuckable design available, for my Glock 27. No matter how I adjusted my shirt over the holster, it was obvious that I put a big gun and my pants and tucked my shirt over it. This depends on your frame size and clothing as much as anything else, but the Glock is big enough that it can really bulge with the wrong body type and holster.
I'd suggest the Versa-max. I use it with a Glock 23.
Good luck!