I hear lots of good feedback about the Eheim auto-feeders but have no experience with them. Overall they get better reports than the Neptune AFS in that regard. Disclaimer, I have an AFS. The main advantage of the AFS over other feeders is that the AFS is controllable so you can e.g. feed in a controlled cycle where you shut down return pump and other equipment, feed, allow a period for the fish to eat and then restart everything. You can also programmatically skip or increase feeding based on other readings, e.g. ORP spiking.
I only use mine occasionally as we like to manually feed. Even when we go away if our house-sitter is comfortable feeding we leave it that way. We also like to feed a mix of frozen food and pellets and the AFS is really only suitable for pellets. I do use it however on occasion. I have had to modify my AFS to not overfeed as I found the stock setup feeds either too much or too little.