There are several that are recognized as the overall top schools considering level of training partners, instruction, and champions produced, but the list can be different for everyone depending on what is most important to you.
One example of a "top school" off the top of my head is Alliance HQ in Atlanta. It has Cobrinha and Jacare teaching, and has produced many beastly competitors and even world champions at each belt level. Some of the names this school has produced include Chris Moriarty, Ian McPherson, and more recently Jordan Schultz.
There's several schools like this around the nation and it would be impossible to just pick one and say it's the best.
Now if you mean "Team" like "Gracie-Barra" that changes things. Gracie-Barra has tons of schools all over the world. Some are better than others, but as a team they're absolutely massive and have produced more world champions than any other team (I think).