Do you want to get a new dishwasher because yours is not cleaning well? Try these steps before you buy a new one.
Be careful how you load your dishwasher. Notice where the spray heads are. If your spray heads are only on the bottom, then the water has to pass through the bottom rack before cleaning the top rack. If you load the bottom rack with large pots, then there is no way to get the water to the top rack. If you need to clean large pots, put them on the top or run the dishwasher without anything on the top.
A dishwasher cleans best with hot water. It does not use large amounts of water like a washing machine, so it takes a good portion of the washing time for the hot water to go from your water heater to the dishwasher. If there is a long distance, then the dishwasher will not be using hot water when it begins washing. Try running water in your sink until it turns very hot before starting the dishwasher.
If you have a newer dishwasher that requires a rinse aid, such as Jet Dry, then that step is usually mandatory. Make sure the rinse aid is filled up in order for your dishwasher to clean better.
Try a more expensive dishwasher soap. I'm usually a generic brand type of person, but I have purchased the cheaper stuff and it just doesn't clean as well. I don't like to get my dishes spotless before going in the dishwasher, so I expect a lot out of my dishwasher. I am willing to spend more for a dishwasher soap that enables me to spend less time hand washing dishes.