I own a Glock 20 and shoot it quite frequently. I really enjoy itand it's not too much gun. The 10mm has gotten an undeserved reputation for having monstrous recoil. It's simply not true, especially in the Glock. It has a large grip and the polymer frame really help reduce recoil. I've had .40's that recoiled harder, and I use full power 10mm loads.
If you do get one, check out
http://www.doubletapammo.com. They have full power 10mm loads. Everything fom 135's at 1600 fps and 767 ft./lb. to 230 grain hardcast. My current fave's are the 165 grain Gold Dots at 1400 fps and 718 ft./lb. for self defense andthe 200 grain XTP's and FMJ'sat 1250 and 1275 fps, respectively,for woodscarry.
I haven't shot the G29, but I have held one and it's not much smaller than the 20 and the 20 is a pleasure to shoot.