I use both platforms in my freelance design business. I can tell you, from many years of experience, that, from within the application, the difference between Mac and PC is pretty transparent. Except for a few keyboard commands, the apps are pretty much identical.
Raw processor speed makes SOME difference in how fast an effect is rendered, especially on the larger files. But all that means is that a fast PC will run faster than a slow Mac, and vice versa. And, in most cases, the differences can be measured in seconds, and fractions of a second.
And, maybe I've been lucky, but my PC doesn't seem to suffer the ails that seem to plague other people's PCs such as compatibility issues, freezing up, or, even suceptibility to viruses. My hardware peripherals seem to all get along and I have few file sharing issues in my internal network.
The list of software apps I use cross platorm include, among others, Photshop, Illustrator, Flash, InDesign, Dreamweaver, Adobe Acrobat Professional, Word, Excel, etc.
For me, at least, the platform wars of the 90s ended back then.
Designer, Illustrator and Desktop Publisher for over 30 years