I almost went with the opnsense route as well, the versatility of this device and the fact it can run on lots of hardware configs makes it hard to find a hw/feature combination that will serve my needs with low power usage and no fan. Also I hope that mikrotiks fw updates have a lower chance of breaking my setup as I've read some bad experiences with pfsense/opnsense updates in the past.

None the less I do like the opnsense setup and might add an additional opnsense vm in the future to play around with!