Pardon me for getting off on a rant.
I just don't buy whole notion of someone being "professionally trained on Mac." I think it's a bunch of nonsense. That's making the operating systems sound much harder to use than the actual truth. Operating systems are nothing more than the front end of the computer. Install/uninstall programs. Manage your files. Kid's stuff basically. Any novice should be able to use MacOS' Finder or Windows Explorer with little problem. If they can't handle it they're seriously deficient in terms of computer literacy.
The real "meat and potatoes" of the computer's operation are the applications that allow the real work to be done. People run applications on computers. They don't buy a computer just to run the operating system.
Adobe Photoshop is very much the same program regardless of whether it is running in Windows or Mac OSX. Same features, functions and interface. Same goes for Illustrator, InDesign, all the other Adobe apps. The same can be said for many other applications shipping both Mac and PC versions. Then that gets into the tired hyperbole of Windows systems crashing constantly.
If a certain "design school" is primarily teaching students how to use an operating system or computer applications and hardly any on the brain-based stuff (typography, color theory, media communications, agency & studio skills, portfolio, etc.) then that "design school" sucks.
Anyone can learn how to point and click their way around Illustrator and Photoshop. It takes a little something else to be creative and focus that creative talent productively. The most important ingredient to good design isn't the flashy hardware sitting on the desk. It's what sits between the edge of the keyboard and the back of the chair.
Having a Mac doesn't make someone a better designer either. I personally know a recent design college graduate who, frankly, is no artist and is really more of an IT geek than anything else. His employer bought him a $4000 Mac Pro tower, two 24" Apple monitors and a whole lot of software. He's hardly doing anything with it. Most of the company's fliers and other promotional material is generated out of another office in Oklahoma City. We're producing all the motion graphics for their LED sign when this guy could be doing it himself. He can't figure out or won't bother to do it. He has the latest versions of Photoshop, Illustrator and After Effects on his Mac. But his desk sure does look fashionable with that Mac sitting on it.
And that kind of gets to why I think some people gravitate to buying Macs. It's electronic jewelry. Digital fashion. Ever notice how many Macs are shown on desks in movies and TV shows. If that was reality 95% of the world's computers would be Macs. I see far more people hauling MacBooks and iPads around without a case than I do any PC user. Gotta show off that light gray aluminum case with the black Apple logo.
I got a big laugh out of the recent news story of a lady in South Carolina being duped into buying a fake iPad in a McDonald's parking lot. The iPad turned out to be a piece of wood spray painted silver. At least it had an Apple logo on it.