I saw a live from the met thing - it was just fine.
I've seen the dci stuff twice - they were both just "ok." of course, I'm not as big of a sound buff as some - I'm only bothered if the sound is fuzzy, electronic noise, or just really quiet. I don't need to be deaf (or have my ears ringing when I leave). But, some do, so I get that. I think I've just been happy to see drum corps, so maybe it didn't matter to me.
but - you figure, if you're gonna pay 13.00ish for a ticket, you'd want it to be decent.