Mac OS X is a very diverse operating system, and will suit the needs of a wide variety of users.Novice or low-tech users shouldn't have too much difficulty finding their way around the simple and beatiful user interface - most things really do 'just work'. Apple actively seem to limit the number of frivolous options and features so as to avoid confusion - elegance and simplicity seem to be guiding principals.
A wide selection of key applications are provided with Mac OS X, wordprocessing, e-mail, web browsing, home movie creation, digital audio and digital photography tools are all there, and many of these freely provided applications are the best available.
If you share your computer with others, it's very simple to create accounts for every user. This is useful because it allows each user to customize their account without affecting others. Mac OS X is also a highly protected system - it's not possible for a simple user to 'break' anything - even if they tried the worst they could do is make a mess of their own account - other accounts and the machine in general will be unaffected. So there's no need to worry about young or novice users rendering your machine unusable.
Technical users are not left out in Mac OS X - the core is BSD unix, and this is freely accessable by those who want to. The command line is just a click away...the Mac OS X distribution is very rich, and all the commands you would expect to find are there.
Development tools are freely provided and actually shipped in the box - so you can begin creating your own software straightaway.
All in all, this operating system really is revolutionary, and with each release it just gets better.