First one had a grumbling drive, drove me nuts, back to Apple. Second one had a much quieter drive, but yellow tinge. I was back and forth about what to do with the tinge issue, I mean I can replace it but will probably get a screen with the same problem. Then my decision was made for when my iMac started to flicker last night, and again this morning. Im going back to my 17 unibody with my 24 external monitor. The 27 iMac has great potential but seems to be suffering from some serious teething issues. Until I can see that these issues are fixed Im holding off.