Not so much any more. It's mostly inertia. At least at the magazine where I used to work. Back before I started working there, they'd transitioned to Macs in art and pre-press because that's where the good software was. A few years into my employment, the big software players in the market started offering dual licensing. I could buy 20, 30, 40 seats and put them on whatever platform I wanted. The software was the same either way with the exception of where menus showed up. When it came time to upgrade the computers in those departments, I thought about pushing for PCs because we could get more bang for the buck. Then I remembered I was hired because of my Mac experience so I kept my mouth shut. Tho we did later transition part of the workflow to PC when we did a software and workflow change.
I think the biggest advantage I can still see is the quality of the hardware and displays. If you get a PC laptop with a cheap-ass display, you'll never be able to trust the color. Same with a desktop. But you can get a good monitor for a PC if you a few extra dollars out of your wallet.