The Auto-Disk is just as reliable. However, the polystyrene hopper is screwed directly down and the threads will break after a while (polystyrene is not an engineering plastic designed for bolting in and out).
The Pro Auto-Disk will last forever, basically, and you won't be buying replacement hoppers every 6 months. It is simply a better design.
If you get the Auto-Disk, buy the Pro Auto-Disk upgrade kit.