Mac users aren't shy - ask Richard
Why not get out into the wider internet and look to see if you can find incidences of Mac users getting a virus, worm or trojan in the wild? Try the same searches for spyware and adware then make your own mind up.
For the sake of argument assume we delete every problem Mac users get to make our operating system seem better. Therefore all Mac forums outside our control should give an untainted view of what we face. This is because, away from the madding PC crowd, the Brand X folks are actually ruthlessy critical.
Regards
rob