video quality when played full screen on a computer is often less than you might hope for. Remember video from DV is 720×480, but most computer diaplays are 800×600, 1024×768, or bigger. So you are making 720×480 video double, triple or bigger in size. It is going to fall apart.
Hollywood DVD titles start with film or HD, so the image quality is better when played full screen.
How does it look on a standard definition TV? That and a computer at 800×600 are the target playback scenarios for SD DVD.
I check my burned DVDs on my computer using 800×600 display settings.
Mike