I'd be interested to hear more about how that switch went and what obstacles you faced whilst carrying it out. I've posted elsewhere in this discussion that my intention is to do the same, for similar reasons.
One thing that did (does) annoy me is that I couldn't get the Apple Bluetooth keyboard to work properly, it would just randomly disconnect and not work until I rebooted. This is the most annoying thing I've found, as I still use a Mac at work (and obviously still use the Macbook), so I'm trying to add onto existing muscle memory and it gets frustrating at times. I do need to look at making it work, or swapping to a new keyboard at work so that keys are in the same places!
Software wise, pretty much everything I use on the Mac I've found suitable replacements for on Mint. There are things that aren't quite as /nice/, but functionally they work: - Transmit - Alfred
However, I still haven't found an email client that 'clicks' for me. I've used Outlook for many many years now, and it works just fine for what I need, so Evolution seemed to be the nearest thing, but it just ... well, sucks. I've opted for just using the online version (I have office365 for my email) so that isn't /that/ major.
But then being able to install tooling for work from just the standard package manager is nice, yes I have homebrew on the Mac, but that's an addon to make things work, and I have to remember to do brew update && brew upgrade every now and then.
Oh, and as an added bonus, because I built the PC I got to spec it as I wanted it - so for the first time in 33 years I own a graphics card! I figured I might as well, add to the lifespan of the machine, got a GeForce GTX 1050 2GB so now I can play games on there as well - in high def.
So basically I've ended up with a much better spec machine, added the ability to do decent gaming, saved a small fortune, can put whatever OS I want on it, all for the downside of not being able to use the keyboard I want. (But I /will. be revisiting that!)