Because Microsoft was leaving Windows XP behind, and my Dell desktop was eight years old and maxed out on memory I went shopping for the next, big thing. I looked at another Dell, but couldn't find any enthusiasm for them or Windows, so I went to Apple. Taking the plunge back to Mac, I went for a Mac Mini.
When I was working at the U of MIami School of Medicine, I was in on the start of computers in art, and everything else. We used both Mac and PCs, because our clients did - you just switched back and forth. My next employer didn't like Apple, so it was PCs for a time. In the early days, Apple lagged behind in animation and then 3D applications, so PC was the place to be for those functions.
Going from full time employee to consultant with that employer, I stuck with a PC when I bought my own equipment. This latest transition has had its learning curve, and a hiccup with internet connection - solved step-by-step, and nicely by the folks at Apple. For the most part, I just have to remember different key sequences and how the places for other functions exist in mirrored locations. This corner on the PC, that for Mac. My laptop has been upgraded to Windows 8.1, so I still have a foot in both camps.
Most important part, do Photoshop and Painter work the same - they do.