I can attest to the garbage disposal working well. I built a grinder from a new garbage disposal, a 1 HP electric motor I got cheap off ebay, and some scrap wood. Where I live, there are "feral" and wild apple trees everywhere, and since it is hard to find the right tartness and tannins in most commercially grown apples, I wanted to try these guys. Thus, I needed a grinder and press. I had tried a food processor, but it was just to slow for the amount of apples I collected. I got the idea and plans for the grinder from Whizbang Cider, just google it and check it out if you are interested.
The problem with the garbage disposal is the motor, it will overheat unless you swap it out with something more robust. I know alot of garbage disposals have 3/4 and 1 hp rated motors, but not all 1hp motors are created equal, and thus the problem. However, the grind is great, a little thicker then applesauce. I used a few old cotton pillow cases to form the cheeses, and used a bottle jack to provide the pressure. I think it worked well, and I am already waiting for the fall to do it again!