Okay, I'm a machead for over 8+ years.
First of all MACS have viruses. Misconception. I will add though, not as many... as they are not as popular worldwide as a windows machine. So you are less likely, expectantly with a virus firewall (Integon virus protection suggestion), then a windows machine.
Apple has moved to a unix kernel (joining them Intel chips, previously windows , has partnered with apple). Using unix, (3rd popular basic language...dos, apple/darwin, unix, linux, there is more), has streamline the hardware. Consider it to be a "a to d" system. Instead of going through a ton of functions, it does functions that are needed only. I will add unix has been around for a long time with supercomputers, scientific research, military, etc...
I worked/operated with Unix and sgi systems (
http://www.sgi.com/ ) which are developed for one purpose only. In my case 3d animation and design. So I have a small knowledge but a big respect to it's architecture and have absolutely no affiliation or financial gain in suggestion them.
So in short.
PRO'S
It's an American company.
Solid system, easy to learn platform (really no difference from a windows system... adding Microsoft/windows has finally, as they like to control everything they do, offered it's products to run on mac).
Streamlined.
CON'S
No computer system is immune to virus
Cost. Getting better everyday, as more buy apple.
Apple store employees can be annoying :]' just kidding.
So I say, do it and not worry and I'll bet that you will like it.
-tinker