Product review (3 stars): the Supco unit is much noisier (the heating element that melts the cubes so they drop from the rotating tray makes a very audible and annoying buzzing noise when it activates)
I purchased this during summer 2014 and it just failed summer 2018. I installed it myself in my Sub-Zero 561, which was a little bit fiddly to do. At the time, I wasn't sure how much longer I would be keeping my aging Sub-Zero 561, so I didn't want to spend the money on the genuine Sub-Zero ice maker (nor a pricey service call from a trained technician), and went with this much cheaper Supco unit and do-it-myself installation instead. It fit properly, and it did work, but you get what you pay for.
In comparison to the genuine Sub-Zero modular ice maker, the Supco unit is much noisier (the heating element that melts the cubes so they drop from the rotating tray makes a very audible and annoying buzzing noise when it activates), it fills the ice bin much more slowly (I can't explain why) and seemingly has a much shorter service life. Based on my admittedly limited sample size, the genuine Sub-Zero unit will last a good 10 to 12 years, whereas this Supco failed after 4 years of normal usage.
So in my view, while the Supco is quite a bit cheaper, it does not work as well, nor will it last as long as the Sub-Zero unit.