What apps/uses do you need on Windows 10? That will directly impact its usability. E.g. Overwatch will be a complete non-starter. Word and Excel wil be totally OK.
The specialized software (it’s for square dance calling) was written in Visual Basic and reads and writes to several databases, displays mostly text, and accesses music playing programs to play music. I don’t think it’s particularly demanding; I was more worried about Windows 10.
I’m running Windows 10 under Parallels 14 on my MBP 2017 running macOS 10.14.1. This is the fourth Apple laptop on which I’ve run Parallels/Windows going back 10 years or more. The experience is solid – and I would expect no less from this year’s Apple laptop models, no matter which one you get. Parallels has improved performance and reliability a lot in recent years, as has Microsoft with Windows 10. I run Windows 10 hr. / day every day in concert with everything else going on on the Apple side of the house. Never a crash or a problem.
Just reporting back: I bought the MacBook Air, updated Parallels, bought Windows 10, and everything is running fine (and significantly faster than it did on the 2011 MacBook Air). I’ve called multiple dances with the new setup and so far, so good.