You would have a hard time to get spyware, adware on your Mac. (Remebering that apparently lots of it comes "preinstalled" on your PC.)
In order to see many of those jpegs and wmv/mov files, many websites launch (or try to launch) trojans and worms. These have, in my 4 years or so of Mac experience, never ever affected my system. I won't even explain any further the same problems that are avoided when using P2P.
I spend an awful lot of time on this board, clicking as many links as I can every day, looking for "illegal" links. I've done this for almost 3 years already - and I've never, ever had a problem. (You may say that you haven't either, but that's because we try and delete the problem links that we find and that are reported. What you you do if you got a reported post that a link crashed someone's system?... or that it set off their Norton alarms?...
)
I can't give you any advice about Mac reliability from an IT POV. But, it's strange that a Mac user would call someone outside of Apple because you have 90 days of
telephone support directly from Apple and a one year warranty.
(Don't forget about the fact that Mac uses OSX as an operating system and that PCs use Windows, which is not an OS but just a program.)
I'm not trying to sell you and I am certainly not some geek Apple devotee. It makes zero difference to me what you use.
I am simply telling you that once you have verified that a Mac run any special programs that you may need (remember the newest Mac can run most Windows software too - with the same software based security weaknesses) spending a little bit more for a Mac can make very good sense.