I've lived with two different boats over the past 20+ years with Martec folders. While backing is not their strong suit, I've got no complaints. Generally giving a short burst of reverse gets the boat backing fine. Are you getting vibrations (means blades aren't opening fully)? Martec folders do need to be reconditioned periodically due to wear in the pivot pin area. Cost is in the $200 area.
It takes more than a short burst of power in reverse before I have control of where we are going. I normally do this out in the channel before entering the alley where my slip is located, in order to avoid hitting anything
But there has never been any vibration, and in forward I have absolutely no complaints.
As for refurbishing, there is a number 931086 stamped on the hub whose format does not resemble what is on the Martec info page, but I suspect that this number means that the prop is vintage 1993, and guessing from the way other systems on this boat have been maintained by the POs, it has never been refurbished. So maybe it is time...
Thanks for the reply.