I'm a Mac user for life but I/we haven't had good luck with past iMac's. My 17" and 24" both HDD needed to be replaced, after 2-3 years. My sister's 20" Logic Board, again after 2-3 years. She was upset but love Apple and refused to go back to Windows so she bought her 27" two years ago but passed on Apple Care. I just got my new 27" last week and when I placed my order back in January I ordered Apple Care. I'm not sure if I learned this from MacRumors or Genius Bar but every now and then I run Disk Utility > Verify & Repair. Any other tips to keep her running smooth?