I initially also thought it was a low battery condition and changed batteries and checked voltage with a meter but even with new batteries the display keeps flashing and the hopper rotates continually.
Based on the lack of responses it appears not to be a common problem which does provide some reassurance that my second unit will not suffer the same fate.
As to other feeders out there I have tried Fishmate, Aquachef and the Rena LG100 but went to eheim because of their excellent reputation and personal experience with their cannister filter, so this failure was certainly unexpected.
The Fishmate worked well but is limited in capacity and feeding flexibility.
Interestingly the Aquachef apparently utilizes the same programming system as the Eheim but the design of its food dispenser tended to give wide variations in the amount of food dispensed.
The Rena with its heater system keeps the food in good condition but the programming system is not as flexible as the Eheim or Aquachef and has to be reset if there is a power outage.
Combining the Rena's ac powered motor and heater with the battery powered programming/timing system of the Eheim or Aquachef would in my opinion be a winner .