I flew the same 212's as did 212man.....and my memory tells me the following.
The SFENA system was rarely serviceable thus was of not much value. When bored you could try to determine if it was working or not or what part was or was not.....but other thantaat it was useless.
The Bell SCAS system was designed by Bell for use in the AH1-G Huey Cobra....which I do not recall seeing installed in our fleet of 212's ....but I used it at other places...was pretty good stuff for what it was....reliable and easy to use.
The Sperry System was excellent kit...reliable..easty to use and the only three of the systems that could incorporate a Flight Directer and was the same on the 212 and 412.
At the Operations we flew the same aircraft, 212man and I, we did not have the luxury of the Flight Director as they had been removed or not installed for those contracts.
Due to my background flying US Army Chinooks where the Force Trim system was ON all the time....I was quite happy to us ATT Mode all the time and use the Cyclic Trim Button to reposition the Cyclic.
I engaged it just prior to TakeOff and went to SAS mode after landing....or turned it off all together if it was the final landing if shutting down,
When landing on Moving Decks....I turned the AFCS OFF.
My view was this....as the AFCS could assist in maintaining a constant attitude....then why not use it. Set the attitude you desire/need....release the Force Trim Button....thus setting the datum...and let the helicopter do its part.
The other lesson learned was never buy SFENA.