Both the Glock 27 and XD Sub Compact are good guns, but I find them much harder to shoot than their slightly larger Compact versions, and nut much easier to conceal. I think if you start figuring out your carry holster, you may find you can go one size up and keep the basic carry options you have with the subcompacts.
I've qualified with a Glock 26 (harder than a sub nose revolver in my experience), but never really carried it. The thing was always too thick for carry in a pocket or simular very concealed carry, or if I went inside the pants, sholder, fanny pack etc. I could always get away with a larger, easier to shoot gun.
My .02 anyway.