I'm using the iMac Retina 5K, 27 w/ 16GB 2400 MHz - it's about 18 months old - replaced another iMac27 that I had purchased in 2010 - for computers they are high cost this one was a little over 3K, but to me well worth it - I have a Dell lap top for work issued by the Company - I used Apple for many years - they are dependable with excellent support - they seem to be very secure - they have their issues good / bad - mine has a problem with pop ups - it does not allow them, i even have issues with this forum when an ad pops up I have to re launch - an irritant but with todays hackers I guess worth living with - their screen clarity is outstanding - the speed is three times as fast as my Dell -with the new software I can run windows programs in the windows mode without issue - the quality has always been top shelf, I've never had an issue with a key board, pad, mouse, the cloud transfer works without issue, printing is quick, program launch is instant - they just work - guess I'm sold on them!!!!