Keep dishwasher drains and filters clean of debris. Reverse flow of water flushes food particles down the drain. Discuss the reported repairs on various models with the salesperson or service person. Search out information on repair records. Compare water conserving vs. energy conserving models.
Many dishwashers have energy-saving cycles.
Look for features that will help keep operating costs down. Low water requirements. Water requirements vary from 9 to 20 gallons per load. Check specification sheets for the amount. Low wattage fans.