Blue Devils do have the most consistent sounding contra section, and there's no way that anyone could ever argue against that with sufficient evidence... just personal preference (and/or bias). BUT... I know for a fact that their contra section has a tradition of sending the drill writer a case of Mountain Dew as payment for the drill (which is noticeably easier than Cadets, SCV, or Cavaliers). And that I do not respect. If we are talking about musical performance, BD wins, but if we're talking about overall drum corps activity performance, then it's still pretty much up in the air. Phantom's contras overblow a lot and hangover releases more than most, cadets are always solid but not outstanding...
I would have to go with Cavies because they showed they can march, play the technical stuff, and play with a good supportive bass sound. And I've never heard them ever stick out or overblow. The only flaw I noticed on the DVD was when the section where they're all in pairs and some sit down and stuff, there's a lick where the tubas have some ascending eighth notes followed by a sustain... and they blew that sustain way sharp... like 30 cents. But other than that... I'd say cavies won 2003.