The only type I've ever used are the rotary ones, where the slot in the top moves round one position at pre-set times. Fairly obviously, only one compartment is accessible at a time:
http://www.amazon.co.uk/Cat-Mate-C50-Meal-Feeder/dp/B0002AR0D8
However, as far as I can tell from looking at them in pet stores (and from viewing them online), the ones with spring-up flaps then remain open.
I've actually found that it's just as easy to put out several lots of canned food around the house, with even more lots of dried food (with water in lots of places too, so that if food gets dropped into one or two bowls there are still uncontaminated ones elsewhere in the house). I reckon that most cats will hardly notice if I'm gone for a couple of nights (but I wouldn't want to leave them any longer) although, since Patches had her 4 children, the longest I've been away from them so far is 30 hours.