After experimenting with several brands/models, my conclusion is there is no single "best" feeder. What works for one type of food may not work well for another. I have at least 6 of the basic Eheim feeders, and they work well provided the food has a uniform size. This is not always true for flake food, and I find it helps to put the flakes through a sieve to achieve a more uniform size. Large flakes, which can clog the opening, get downsized going through the sieve to reduce/eliminate this issue.
A helpful tip - the Eheim meters the food through an opening which is set via discrete click-sets. If one click is too little but the next is too much, you can still set it in-between, but I suggest you add a piece of tape to keep the opening from slipping to a discrete click-set.
For fish whose diet is large pellets, I use a pond feeder by Fish Mate. It handles the large pellets and has a decent capacity.
Eheim also has a twin feeder. It looks like it should handle the large pellets, with a screw-type delivery system, but large pellets are dispensed with way too much inconsistency. Also, the hopper lacks the capacity, though it could be easily modified to handle much more.
Always test your feeder/food combination to make sure it is dispensing what you think it is dispensing, over many cycles. There is nothing worse than realizing that a large flake or some moisture blocked the opening, reducing all future feeding cycles to nothing. Also, pull the batteries when you are not using the feeder. Battery leakage is increased in the higher humidity environment found right above an aquarium.