We recently replaced a broken firmadoor unit with a
Merlin 430.
The Merlins appear to have better motors and a better de-clutch/drive mech than the B&D and firmadoor. Don't know about soft start but most/all have motor stall detection & reverse.
With the Firmadoor, our door wrapped it's convolutions on top of the door jamb around itself & we couldn't de-clutch it because all the drive gears had pressure applied to them. This cause the drive cogs to rip off teeth. This was a problem with it's drive design...even though it had a de-clutch it would not work when really needed.
With the Merlin, the de-clutch is directly from the drive gear thus the above situation could never arise.
Any way 2C worth.