I have a roll bar in my vert. I think they look good myself, but I put it in for safety and when tied into subframe connectors it made my car much stiffer and soild feeling.
I can still fit two small people (teenage daughter and friend) in my back seat. And, I have raced with both top up and top down. I think top up may be more aerodynamic but top down is more fun.
One day on the freeway, I watched a VW cabriolet (not sure about that spelling) with a roll bar, flip 1/2 a dozen times right infront of me.
I pulled the girl out of the car and she literally did not have a scratch on her.
Without that rollbar and a seat belt, I'm sure she would have been dead. That was enough reason for me right there.