I switched to Mint (Mate) around 2012 or so because of radical UI changes made by Canonical. At the time, the "mobile revolution" was the big industry trend. Windows 8 had come out which was designed for touch screens (and people hated it) ... and Canonical released a new default desktop environment (I think it was Unity? Memory is fuzzy). It was shocking to me and when I complained about it, a friend recommended Mint.
The nice thing about Linux is that you have max choice. That can pose problems for new users who might be a bit overwhelmed but we shouldn't pretend that Canonical "owns" Linux or that everyone is necessarily going to land there. I recommend Mint when people tell me they're thinking of giving Linux a try. Haven't given Ubuntu a second thought in years.