One of the only rental shops in Portugal with a website that works correctly! I tried to reserve through Enterprise rental but their website wouldn't allow me to choose any of the available pick-up times, so gave up and rented from Sixt.
The staff are super friendly x energetic, and helpful for explaining about driving on the expressway in Portugal. The car was given with explanation on setting gps to English and fuel tank.
Because the roads are narrow, I accidentally scratched the side mirror but returning the car was a breeze. They assured me and made me feel relaxed about the scratch I had created.
Accessing the rental shop is a little difficult if you walk from the nearest subway station so make sure to take the bus there instead.
I'll definitely be renting from them again soon.
One thing which I wanted to know was the expressway toll charges. Not sure how much I was charged each time I crossed, but other than that, the staff emailed me my invoice. Really helpful especially for foreigners booking a car from their hoke country.