Product review (5 stars): Value for money, easy installation as advertised - one trick
Calling a repair guy would be at least $150, and installation of this unit is simple.  The "one trick" is that in my unit - a KitchenAid freezer-on-the-bottom - (KitchenAid Model #KBRA20ELWH01), the water is supplied from a horizontal tube.  In this replacement unit, a "knock-out" is provided to allow for the tube.  Installation means you have to cut out the pre-scored knock-out with a sharp knife).

Removing the old unit means removing the freezer drawer from the unit (nothing tricky about it, but it can be awkward) removing three screws and disconnecting the power harness.

Installation meant transferring the old harness to the new unit, transferring two clips from old to new, screwing in the three screws, and plugging the harness back in.

The unit comes with two different harnesses and a bunch of clips, but I just used the old ones.

It took some time - probably five hours to chunk out the very first blocks of ice, but the ice has been producing freely since then.

I installed the unit using a drill, a screwdriver, and a knife.  It took about 1/2 hour to 45 minutes tops. The unit works this way:  the ice tray is filled via a tube from the appliance.  When the ice is formed, a heating element in the ice tray kicks in, and the white pegs rotate to flip the ice cubes into the holding tray.  It appears that the control unit in my original unit became corroded, which prevented the heating element and flippers from kicking in.  Whatever.  I include this info only because I would have liked to have known it before purchase.  Cleaning the corroded control unit would likely fix the old unit, but for this low cost, I went ahead and put the new unit in.