Yes! We rented the convertible Sebring a few times, and even if the car was boring, driving with the top down was awesome. If you get a Mustang or Sebring (do they still have them?), you should have enough space in the trunk with the top up for the drive from/to the airport, and the rest of time, without the luggage, trunk space won't be an issue.
We rented in September, in the high heat & humidity: hats firmly attached & sunscreen for the sun, and air conditioning on for the heat. Yes, we had to stop on the side of the road to push the button and wait for the top to close a few times when the sky was black, but really, it is a 2 minutes thing! We would always rent convertible if it wasn't so expensive.