M1key, let me know where your buddy got his gen 4 g26 as I was under the impression that they will not come out till early 2011.
I currently own a Gen 4 Glock 19 with the 04 recoils spring. I was a little perturbed when I took to the range the first day. With the factory mags I had a failure to feed on the third round through the gun, or fifth round if you count the two test fired at the factory.
Then had to more malfunctions (slide failing to lock back on the last round, and another failure to feed) while running through 150 115gr walmart rounds.
Took it home, cleaned it, lubed it, locked the slide back over night, and manually racked the slide 100 times while watching t.v. which probably scared the sh#t out of my neighbors. Since then, I have had zero issues with it and don't plan on running the 05 spring that glock says will be out late this month.
In terms of the frame, I really like the reduction of the hump on the back. The new rtf like texture is really nice on the range but have heard that it is irritating to the skin if carried without an undershirt. Also, the new gen is new enough that there arent as many accessories for it as the gen 3. Just a few things to think about.