Here's my take on the laptop situation...
I'm not a PC person so I can't really recommend a particular model. Most people who have PC's in my program have Lenovo and ASUS.
I am a Mac person and will always be. Over half the people in my program have Mac, so it's not uncommon at all. We do have to partition our hard drive and install bootcamp to be able to access some of the software we use in our core classes. I will say something, when we ran RISK Palisade simulations (on the windows side of my Mac), my computer was way faster than any PC, including the professors'.
So my final advice is, if you are used to PC, get a PC. If you are a Mac person, don't be afraid of having a Mac in business school.
P.S. Tablets are useless for class. If you want a tablet in addition to your laptop just for the sole purpose of downloading e-books and textbooks, be my guest - however it does not replace a laptop in any way.
Also, If you guys want some time to kill before enrolling your program and want to get a head start in your career search, check out pymetrics. It's an online neuroscience game-based career assessment platform that connects you to companies and jobs based on compatibility. Pretty awesome.
https://bit.ly/1JxEviS