I also carried out this experiment, mainly cos I couldn’t afford a Mac for a while. Completely agree with all his comments except: the default terminal in Ubuntu is a gazillion times better than Mac and that makes a huge difference. But ultimately productivity suites matter, webmail sucks, and all of the email clients on Linux were awful. That’s a showstopper for anyone doing a lot of office or management work.
Thunderbird is pretty good and in my experience, less buggy than Apple Mail, especially when using providers other than iCloud. My wife absolutely hated Apple Mail, primarily because it would forget passwords and stop syncing/sending. So I moved her to Thunderbird and now she's happy.