We have an iMac (21 inch) which we purchased about a year ago and I have had no major problems so far. However, I am thinking of buying another for my wife and understand it will be equipped with the Maverick upgrade. I have read a number of bad reviews of this upgrade and I don't want to have two computers with different systems because I will be the tech support for my wife and it will be enough of a challenge without the problems of using a later version of software on her new computer. (At this point I have no intention of upgrading my own computer and risking problems with my other applications). Any advice would be appreciated that does not include a major amount of technical expertise on my part.