We were surprised at check-in to find there was an extra fee to park our rental car overnight, so we decided to return it early and take the free shuttle instead. I definitely recommend this—it was much easier to drop the car off the night before and just take the shuttle to the airport.
Tip: if you want the hotel shuttle to pick you up after returning your rental, you need to go back to the airport terminal and call the hotel to let them know where you are. We saw a big group who didn’t call ahead, and when the shuttle showed up with only a few seats, they got really upset and held everything up. The driver stayed calm, but it would’ve been smoother if everyone had followed the instructions