As a laptop OS it destroys Windows everywhere. The trackpad alone is worth any extra money over an equivalent Windows laptop. On top of that you have the exceptional build quality (my MB is 4 years old and still feels as tight as day one, can't say that about a plastic Dell/HP/Acer), I can still get £400 on eBay for it which you can't say about any other 4 year old laptop and the OS still feels very fast.
Think about it this way, your iPad and iPhone feels like the hardware and software were designed to fit together perfectly, it's exactly the same with an MB and OSX. You use one for a few weeks and you just think "why would you do this any other way than Apple have done it" then there will be a day where you have to use a Windows laptop and you will want to kill yourself.