Perhaps a definition of what you mean by crummy and bad will help get you to a solution.
Are you using Export -> Quicktime Movie, … or Export -> Using Quicktime Conversion?
If you are using the Quicktime conversion option you may need to take a look at your codec and its settings.
What is the duration and dimensions of your clip, and what is the exported file size? From this we may be able to tell if it is heavily compressed through your selected options and that is why your export is looking bad.