Bought an returned a 2017 i7 iMac. Ordered an i5 iMac instead. In the meantime I'm back to my old machine, which is a non-Retina 2010 i7. Performance is fine for basic stuff (aside from the lack of SSD), but using it now reminds me of using a VGA screen which is out of pixel alignment. I will be using this 2010 iMac as a second monitor, but I'm not entirely sure how long I'll be able to last with a non-Retina 2nd monitor.