Ivy leagues are not known for their engineering programs.
That said, they are better known for sciences. If they do science, chances are they should go on to do a grad program, which is offered at Ivies.
Ivy leagues are well-respected generally and you can get a lot of connections that people at other schools may not necessarily have (e.g. - if you wanted to get an MBA later you can take business classes there).
I agree that if the student loves the school then there is no reason to chance going somewhere they may not like.
It is probably better to do really well at a good school than do ok at a slightly better school. The only exception being if the school you did "ok" at was top ranked.
These are all very good schools so it isn't a critical distinction IMHO.