EF will only query exactly what you ask for and will execute the query only at the point you actually iterate or request an object. For changes, EF will only hit the database when you call SaveChanges() on the context. It's an abstraction that works with very few "leaks".

Eloquent also has object collections. Both frameworks have similar methods for filtering and querying. Eloquent is much more clunky (because PHP) and the underlying conceptual model is different (ActiveRecord style vs. DataMapper style). I certainly would use Eloquent for PHP projects but I definitely wish PHP could do something like EF.