I thought I wanted the MacBook Air, because almost all of my work is writing.

But, after going to the Apple Store and talking with someone there, I went for the MacBook, which was actually cheaper, but had higher performance than the Air. Mostly I wanted the different ports, though.

What I have learned, after purchasing Apple computers since the mid-1980's, is that you should always buy as much Mac as you can afford. The hardware and software lasts and works for a LONG time, and you are never going to know, day to day, if the few extra Mhz or RAM or whatever, actually made any difference.

You are just going to use the machine. Every single day. So future-proofing yourself as much as possible (by buying the most you can get) is always a good idea. The other option is to buy one level down from the top level, and then when you run into problems you blame yourself for making a "bad" decision. If you buy a top-of-the-line machine, then you know you have the best hardware you can get, so when you max it out, it isn't such a big deal.

Mac vs PC

This is not a "one is better than the other" choice. I have used both operating systems extensively, and they both work just fine.

But one OS seems to work better for some people, and the other OS seems to work better for others. It's Coke and Pepsi: they are pretty much the same, but some people love one over the other.

Since you are adept at the Mac, I'd suggest you stay with the Mac, for no other reason than you are familiar with it, it works for you, and you are producing great content on that machine. Why mess with something that works?