Tempis fugit... Technology fugit...
Since I have one foot in the consulting world and one in the photography/graphics world, I stick w/ PCs. In the business world the PC is still the standard. As far as I'm concerned it is six of one, half-dozen of the other.
I work with others in LR & Photoshop on Macs and there isn't a difference worth mentioning, except perhaps cost.
Find a local computer service / builder and build a PC with some real grunt for about half of the cost of an equivalent Mac. That's what I did after my last HP Desktop couldn't cut the mustard w/ LR 4. I spent some time finding the right PC builder, having lots of conversations about needs and sweet spot re components. Worth the effort.
My machine cost about 2k and an equivalent Mac would have been considably more expensive. My machine is flawless after six months of intense use, and if anything goes south my dependable "computer guy" is about ten minutes away.
2 SSD, one for system & programs, 2nd for catalog & scratch/cache, third fast/big HDD for data. Intel Ivy 3770, 32 gigs RAM, good video card, lots of esata and USB 3.0 connectivity. Screams.
Best of luck as you move forward. A good back-up regime is essential no matter what you do. Rust never sleeps.