Has worked well for me, but keeping in mind that email is probably about the hardest thing to properly self host.
DMARC/DKIM/SPF/MX records have to be set up properly, DNS for auto config and such preferable, and dealing with a myriad of mail IP blacklists (good monitoring service for free: https://mxtoolbox.com/) all come into play.

It's really just the first additional outside of the primary. My employer has a self+children option (in case the spouse has their own plan) that's around the same as a self+spouse.