The few times I've had to use AppleCare in the past haven't been bad at all. It might depend on the store you go to or the particular "Genius" you get. Both times were related to the 17" G4 PowerBook. Once was trivial and fixed right there in the store (a clippy thing on the underside of the spacebar broke, so they put in a new spacebar.) The other was a faulty backlight and involved sending the laptop out for repair and waiting. And waiting. Their repair facility was out of a particular part and once the waiting got to be long enough, they gave be a brand new laptop (1.6 GHz, compared to the 1.0 GHz I brought in.)

On the whole, the experience has been not super-outstanding-great, but as good as I would expect. The geniuses have been helpful, and I think happy to work on something that is not yet another "my iPod stopped working" issue.