I love Apple products - this review has to do with their "Geniuses" on staff. I brought my iMac is that wasn't booting. It was only a year and a half old.
The tech listened to the startup once or twice and told me it was logic board failure and since I didn't have Apple Care, I needed to buy a new computer. She seemed rushed, so I wanted a second opinion.
I brought it to the uBreakiFixIt store and dropped it off - they offer free diagnostics. I got a call back a couple days later that they replaced the CMOS battery and it's working. This fix cost we a whopping $59 - a savings of $1150 from the Apple store's solution.
I know where I'll be going with a problem in the future...