Been in three times so far. Just thought I'd share my Genius Bar experience.
Brought my 27" iMac in. Hard drive has been chugging after login and I get slow downs and random freezes every once in a while. He couldn't pinpoint it, but agreed something was off. It has been like this since I bought it (had Lion on it), and I've reformatted and started from scratch and it still occurred.
So, he couldn't confirm it was the hard drive, but he wanted to put a new drive in. Everything else checked out okay, so we did the drive.
Picked it up today with the new drive installed. I had backed everything up twice - Time Machine and separate backup. However, I completely forgot that I had removed my Pictures folder from Time Machine due to all my huge Aperture libraries that are there and gone all the time.
I backup those libraries to three drives and I use the Vaults feature too. All fine, except there is one other thing in the Pictures folder - the iPhoto library! Which happens to house all the videos from my iPhone, including videos of my 6-month-old daughter.
All of a sudden I was one of those customers I swore I'd never be. I called and explained and they said to come back in. I bright my MBP and the plan was to check it in and have them throw my iPhoto library onto it.
Once I got there, the employee looked at my waiting wife and baby and said he'd be right back. He came out with the original hard drive in an electrostatic bag. They gave me my original drive back and I popped it into my enclosure at home and got my iPhoto library back.
Obviously I won't be using the old drive for much since it could be iffy, but it's great that they gave it to me.
Awesome service, though there was a bit of wait each time. Either way, they went out of their way to help me and I'm grateful.
27" iMac 3.4ghz i7, 12gb, 1TB + 256gb SSD | 15" Retina MacBook Pro 2ghz i7, 16gb
iPhone 5S 32gb gold His | iPhone 5 black 32gb Hers | iPad Mini Retina 64gb | iPad 3 32gb