PiPi636

Personally own a MacBook Air 2017 that I use for pretty much everything. Agree with Lord Vile that a higher storage air is a better purchase than a base model pro. Both the office apps from Apple and the office suite from Microsoft work perfectly fine. I do prefer to open documents in the app they are created in; exporting and importing don't always play nicely with everything (SmartArt in Microsoft Office is a great example).
 
I don't really understand what you mean by 'missing a whackton of things'... I never had the idea that I couldn't do something. You might sometimes need a minute to figure out the 'Mac way' to do something, but there was never anything I completely couldn't do.

Apple have basically abandoned industry standard graphics APIs and gone with their own thing. Unless you specifically want to target macOS, you'll likely find more and better tools on other machines.
 
This isn't going to be that important with basic unity stuff, but if you end up going into deep graphics magic, you may find vulkan/dx12 better supported at the bleeding edge than metal, and if developing for an indie game, the first two will let you develop for a wider audience.
 
But unless you're doing some really experimental stuff, that shouldn't matter too much, and you could just go with an older version of openGL. Going with macOS, since you're familiar with it, may serve you better in that case.