My dishwasher is not the greatest, but it came with the house so I have to cope. I think of it more as a dish sanitizer - it doesn't deal with food being left on the plates, and since it's DD's job to load the dishwasher, you know corners are often cut when no one's looking. I think that there's a drainage problem, but I'm afraid to take it apart and see.
To cope, once a month or so I wipe down the inside with a damp rag, focusing on the seals. Then I dump a cup of white vinegar in the bottom and run it empty. It seems to keep things cleaner and fresher smelling.
Deb