Product review (1 stars): They work for about 2 years, then the tray will not release the ice.  Sometimes solution below will work for a while.
First, let me say that it IS super easy to replace this,  I should know, I have now done it 2 times on a 5 year old refrigerator.
What happens is that the plastic flexible ice tray either gets rough from hard water or less flexible over time.  You are then forced to buy a whole new icemaker for what is basically a two dollar part.  They will not sell you the tray alone.

A helpful hint, if your ice is sticking in the tray (so that the tray is stuck in the flex position) AND you want to try to fix it yourself do this:
Remove the tray of ice to make it easier to access

1)  use a hair dryer to get the ice loose enough to remove the stuck ice
Under the right hand side of the icemaker is a button that cycles the tray system.  Push it.  Let it cycle.  Now you have two choices depending on how scaly your tray is:

a) Sop up the water with towel.  Fill tray with vinegar.  Wait an hour.  Push button to cycle tray and catch vinegar.  Repeat a couple times to clean tray.

b) If ice still gets stuck you can actually remove the tray and soak it in something stronger for scale removal.  You need to carefully pry the little tabs from the temperature sensor underneath then wiggle the tray out.  Soak.  Reattach temp sensor.  Wiggle tray back in.  Do this at your own risk, you can break the icemaker trying to wiggle it in.  BUT, if it is already not working you do not have much to lose.