The big news for some of us is that Exim has been dropped from ports. Here is a good article about transitioning from Exim to OpenSMTPD:

https://nxdomain.no/~peter/time_for_opensmtpd.html

I tried using OpenSMTPD a long time ago, shortly after it came out, but things were not stable enough. I guess it is time to give it another go...