I just completed my email migration away from Gandi this weekend. I figured if I had to really start paying for it, I might as well get something better than their offering or move to something cheaper. If I'm paying ~$4/mo per user, it really starts to seem worth it to spring to something that offers a lot more for similar pricing. Then there's lots of services out there which offer cheaper prices with more features. For truly just a basic mailbox <$1/account can make some sense, but basic email only for that price is crazy steep.
I ended up migrating to Zoho. It took about an hour getting accounts set up, DNS records changed, and data migrated. Importing data through IMAP went really smoothly. I probably could have gotten by on the free tier but a few family users didn't want to use the apps and preferred the Exchange ActiveSync functionality to have a more system-native experience on platforms like Android and Windows.
So far, so good.