So my iMac is 9months old and still under its warranty obviously. i noticed that when i plugged in an external monitor i would get green flickering on the external screen, so i took it into the apple store in southampton who were more than happy to fix the issue. (logic board was replaced). when i received the unit back a day later i noticed large pieces of dust under the screen. (screen was immaculate before) so back to the apple store for them to clean it. i was in store for over 5hours with them cleaning it several times but could not remove the dust. there are now finger prints under the screen as well. The manager of the store told me i would have to live with it. Every time it would go back to be cleaned the genius would snatch it of the table and go back in a huff. like he could not be bothered to sort it out. The manager was SO rude and condescending to me, the level of customer service i received in store was unacceptable. it's not like its a cheap imac either, i bought the best. in the end i ask if i could just have my money back, or a new screen or a new computer anything that would fix the dust problem but the manager said he wouldn't. When i returned hope i got onto the phone to apple care and one of their customer care representatives told me the same, they were out of order. He called the store but they flat out lied and told him there was no dust under the screen. So now i have had to send my iMac to an independent 3rd party for another opinion. i just feel a bit cheated.