The battery life on the 15" MacBook Pro isn't awful, but it certainly isn't fantastic. So like many owners, I've got a spare battery... actually, I ordered it with the computer! Recently, one of the two batteries has been doing something very strange: As the battery gets nearly completely drained, the machine turns off. It doesn't go to sleep. It loses power and turns off. (Like pulling the plug on a desktop computer.) Not very nice. Worse still, there's still some charge left in the battery, so it could have made it to sleep without issue.
I wandered into the Apple Store on Regent St., mentioned this to one of the Geniuses, and a few minutes later he commented that while they couldn't find any similar reports in their tech database (gotta' love being unique, I guess), they were just going to swap out my battery for a new one. So now I have two properly working batteries, and no fear of my machine randomly turning off anymore.
All in all, I'm pretty impressed, not only with the care I received, but that someone in a store was able to make a decision to fix my problem, instead of saying something like "Sorry sir, we haven't heard of this problem before... so we can't really do anything about it," or asking to take my laptop away for a few days of diagnosis.
One more happy Apple customer.