I've been using one for a few weeks now. I know @Da_Neefer also has them for his tanks.
The best part of using these over my old Neptune Feeder:
1. My tank is small, the feeders I've used before required me to tap up the hole and it was wildly inconsistent. The Plank allows extremely fine control of how much to feed.
2. The feeder was crazy loud. I couldn't do work calls (It's in my home office) right when the feeder went on. The plank is basically silent.
3. I had an acrylic square thing attached to the feeder to keep the food from immediately spilling into the overflow, but even that was hard to use. The plank does a great job of stirring it in.
The best part of using these over my old Neptune Feeder:
1. My tank is small, the feeders I've used before required me to tap up the hole and it was wildly inconsistent. The Plank allows extremely fine control of how much to feed.
2. The feeder was crazy loud. I couldn't do work calls (It's in my home office) right when the feeder went on. The plank is basically silent.
3. I had an acrylic square thing attached to the feeder to keep the food from immediately spilling into the overflow, but even that was hard to use. The plank does a great job of stirring it in.