Bought 27" i7 iMac that had the following issues: choppy video, menu bar not loading, broken wifi hardware, USB devices not being detected (or mounted), and 3rd party s/w not staying installed. Our nearest Apple store couldn't explain it, but they swapped it out for another one. We all sat in the store and set the second one up and it had the same issue. Bad batch? Only option is to wait it out, or try a mini. Wife still wants one, but not one that exhibits these kinds of issues, and the stores have no answer--other than return the unit or live with issues. BTW, if one buys an iMac or mini from Apple's online store can they be returned at any of the retail stores?