I'd only be using Macromedia Studio and Adobe Creative Suite, but I think the stability in itself is a reason to have it. I'm not sure how practical and convenient (strange as it sounds, I'm not sure I like the idea of switching between OS's, even though there will be increased functionality and productivity) the idea is, but it's neat.
They have the best hardware/software to do the job right. For examples look at any major recording studio or graphic design shop or video production company they all use mac.
They can do everything you need them to do in the time it needs to be done without any problem.