The thing with this is that sometimes a line-up of really poor characters leads to awesome books: Justice League Europe/International was Blue Beetle, Booster Gold, the Crimson Fox, Guy Gardner.... and that book was hilarious and fun, if not exactly traditional epic superheroics.
And then on the other hand you have line-ups that you expect to be poor that end up being even worse than you expect: case in point, Justice League Detroit. You really can't argue with that single statement.
And with the best moments in a team, it's usually the iconic character that make it work: Morrison's JLA is a perfect example. Or like in Daredevil born again, the Avengers look so damn awesome because it's Cap, Iron Man, and Thor who show up, with no Triathalon or Justice or Rage to mess things up.
Anyways, in answer to the original post, I'd have to go with the Avengers as having worse members. An Avengers line up of like Iron Man, Cap, Thor (alternative, Hercules) with maybe a little Hawkeye, She-Hulk, The Vision, Ms. Marvel, the Wasp, and a non-crazy Scarlet Witch and a few others. That's a good Avengers team.
But then you have like... Darkhawk. Arachne. Demolition Man. Justice. Firebird. Firestar. Silverclaw. Rage. Non-cool Captain Britian. Mockingbird.
And I'd rather read about some of the lesser JLA members than that: Elongated Man, Blue Beetle, The Atom, Doctor Light, Rocket Red, or Aztec.
Just as long as it's not the Red Tornado. I f*cking hate the Red Tornado.