Nowadays, PC "ultrabooks" like the XPS13 and UX305 are similar in size and build quality but come in a variety of configurations with better battery life and a choice between low power low res screens and high power high res screens. And they're significantly cheaper.
Linux works perfectly on the Intel chipsets these computers use as well with open source drivers from Intel themselves. I haven't had any problems with Ubuntu, my install is pretty much stock Unity.
I used to work for Apple and still have Apple stock. As a stock holder, I think they need to make a similar leap with their computers as they did back with the MacBook Air.
The two things I would most want from them are a 40" curved screen iMac and and a MacPro replacement that looks something like the Razor Blade Stealth where a full powered GPU attaches via USB-C. I mention these 2 designs because they require a lot of tinkering to get working on the PC side and while Apple doesn't really make anything new, they do polish existing technology extremely well.