I am still happily running FreeNAS 11. I haven't updated to 12 and it's name change to TrueNAS. Anyway, the amount of janitoring I have to do with it is very minimal. Over the last year, less than 1 hour of time spent total.
Another very happy freenas user, been running freenas (now truenas) for 8 years. Other than hard drive upgrade and one hard drive failure it has been pretty smooth. My overhead in last year has been maybe 5 hours of upkeep.
