is an interface between hardware and user which is responsible for the management and coordination of activities and the sharing of the resources of the computer that acts as a host for computing applications run on the machine.
Pro: 1) No need to worry about viruses or adware. 2) Nice suite of integrated applications (iLife). 3) Nicely designed hardware. 4) Shareware applications tend to be better designed. 5) An intelligently designed OS (adding a network laser printer is a breeze).
Cons: 1) Accessories tend to be more expensive (hello TV tuners!). 2) Not compatible with a LOT of PC hardware. 3) Safari & FireFox on Mac don't work for all websites. 4) Command key is in an awkward position. Control key on Windows makes more sense. 5) Some software just not available on Mac (hello MSN Messenger with video).
New nodePros:open source, stability, variety, thousands of apps for everything imaginable, constant updating and improvement, etc.
Cons:games, incompatibility with some newer hardware/devices