$2800 on a laptop with only 16GB RAM that you're going to run linux on anyway? If you're going to run Ubuntu, why not get a Lenovo for much less and with notably better legitimately "Pro" specs?
Build quality. It's difficult to find a computer that matches the quality of a MacBook for fit and finish, trackpad quality, and battery life. I haven't used the new one, but the 2015 models were among the best hardware on the market - regardless of what OS was installed.
everyone who argues that and then try to prove their point ends up comparing budget pcs. so tiring.
also my company is full of 2012 and 2013 macbook pros that crash and burn with several hardware video card build issues that for some reason it was never able/willing to return.