I agree - it probably depends on the apple store personnel that you get. I love the anti-glare film, and it was not too hard to put on. If you want to be extra careful (read: anal) like me, you'll put on gloves, work in a dust-free area, and practice lining up the film multiple times before actually putting it on.
i put it on my self on my first iPhone 3G. When i got it replaced yesterday because of a crack i told them i had a screen protecter and he was like ok! he spent about 5 minutes getting the screen protecter perfectly placed on my new iPhone 3G. SO just ask the guys at the genius bar and they'll help you out