The reason that Mac's dont have Viruses is they are only 6% of the market share. (to give you an example, acer is also 6% of the market share). If you are out there making viruses, would you make it to affect 6% of the market, or 94% of the market. If macs do get more popular, then they will start getting some i assure you.

The main differences are this:

1. Macs are more expensive for hardware that is behind pc's. They are just in the past year or so using intel processors, and the ones they use are slower than high end pc's. They also charge you about twice as much for the same or less hardware.

2. Macs are more idiot proof. Everything is simplified. If your not very savvy with computers, then this is a good thing.

3. there are some issues with compatibility, however if you are just using it for school and home usage then you shouldnt have any issues. But you can buy a lot more software for a PC, than a Mac.

4. In the Graphic's department, macs kick ass. They are faster at rendering graphics and have true color printing, unlike a PC. So if you do lots of rendering video or graphics, then its the way to go.

It really depends on you, but you can buy a high end Dell laptop for probably 800-1500 bucks, and do everything you want, or a mac would cost you 2000-2600, for the same or less hardware. That is what aggravates me about macs is they over charge you for everything and everything is proprietary. And yes you can buy a refurbished one, but you can also buy a refurbished Dell high end laptop for around 600-800 bucks, so still cheaper than mac.