The top is better because if the bridge ever falls down your car won't get squashed. But you will get hurt but not as bad as the people on the bottom though. It is also better because you have a better view of the city if you are just there to visit .
Yes for lower level, no for lower level. I kinda like to see what lower levels of bridges look like. It's a lot of fun. I like the GWB the most. American Electric NEMA luminaires on the bridge are down right awesome in every sense of the word. NYC bridges are fascinating.