I have the Apex one.
No complaints really. Yes it is noisy.
Mine is installed over the return section of my sump instead of over the tank. Works well, food drops in and return pumps pick it up and randomly sends it to the tank through the returns, fish get to chase the food and it doesn’t all come out at once but usually all out in a couple of minutes.
Don’t really get too much settling in the return section so no real buildup.
On the feeder you select pellet size by slide. It’s a little finicky to find the right size. The small is a little too small and the next size up seems to dump a little too much. I guess it depends on size of pellets.
The drum is removable but the one time I accidentally dumped the pellets in the tank while trying to remove and add more.
Nice thing is it integrates with the Apex, pumps slow down and easily programable.