Update- I purchased the aquachef and did not like it at all. I sent it back. The main beef I had about it was that the bracket which clamps on the side of the tank was extremely too small. I basically had to remove the suction cup to even get it slipped over the tank wall. I then tried to reattach the suction cup. No way! I almost stripped the plastic thread. The box said "Fits most aquariums", but really, a tank wall is a tank wall. My other complaint was that the unit itself is very large. This is very subjective but I have a wood cabinet hood and the feeder stood too high and bumped into the hood.
I next tried the EHEIM. This unit was much smaller and fit very well, but the unit dispensed food too randomly at the same setting. On the same setting, one time it would spit out 5 flakes, the next time 50. What gives? This too will be returned.
I think I may just go back to the drop in block feeders.
Anyway, I thought people would be interested in my reviews.