I use the Rondomatic feeder from Grasslin (got it from thatpetplace.com). It's a bit big, doesn't have alot of bells and whistles like digital readouts, and it's not very cheap, but here's what I like about it:
- Individual food trays that allow you to put a variety of different foods in there or even meds/supplements. Also, you can see exactly how much food is going in the equarium instead of having to play around with quantity settings to get it right.
- Great flexibility in feeding schedules. You can feed up to 5 times a day if you want, skip days, vary foods between days (see above), etc.
- It attaches to the side of the aquarium instead of sticking to the aquarium cover like many of them do. I generally don't have a cover on my aquarium, so this was a must.
- Electric instead of battery powered.
The only real issue I've had with it is if you live in a real humid area like Florida, flake food will tend to stick to the bottom of the feeding trays, so you don't get quite as much food in the tank as you planned. It's also not super easy to use, but it's not exactly rocket science either. If you can't get it up in running in 15 minutes, then you might be a. . .nevermind.
Oh, I just found a website that reviews some fish feeders. Ironically enough, his review of the above feeder sounds quite a bit like mine:
http://www.wetwebmedia.com/ca/volume_2/cav2i4/impressions/feeder_impressions.htm