I can't speak for the Model Y - but with a family of 6 myself, I was kind of eyeing a 7-seater Y too.
That said, I do have a 7 seater 2015 Model S now, ha d it for the last 3.5 years and it is fun to drive. The jumpseats are cool, but only my younger 2 kids (5 and 9 y/o) fit there anymore...