I got a chance to handle a Gen 4 G22 today. And I will buy a Gen 4 G17 when it's available. Like others have posted already, Glock improved, no "perfected", the frame!
For my hand size, I'll go without any additional backstraps. And the placement of the mag release was near perfect for me. I only had to modify the grip, just slightly, to get positive contact with the release button.
I saw this on another forum and I have to agree that there is something different about the trigger. It seemed smoother to me, not lighter, just smoother.
The store I was in listed it for $649, but that's the stupid price. I plan to use my GSSF certificate later this year to pick up the new G17. I can see IDPA/USPSA shooters taking this gun to the match. I have handled a G34 and liked the trigger and longer sight radius but the new G17 should give it run till Glock comes out with an updated G34....Overall, I think Glock hit a home run with this one....