Always rent from Sixt, they are a great company with good rates, great customer service and overall a good experience. Basel pickup is confusing, however. Once side is French and one is Swiss. Please note, if you get a car from the French side, but plan to travel in Switzerland, you will have to get your own Vignette or risk getting a ticket. I think all cars rented in Basel, regardless on which side of the Airport - French or Swiss, should come equipped with one