Pick up the car: Everybody seemingly wants to rent from Sixt, even though they have many more rental stations next to the Sixt-Container. I reserved there myself as I had good experienced with Sixt in Austria, but I wondered whether it was the right choice as we were waiting there, outside in the sun.
After a while we were asked to step into the container and do the formalities, which basically meant that we had to deal with an unfriendly sales person who wanted to sell as an additional insurance for everything plus a service to refuell the car when we bring it back (there is a fuel station on the way from Split direction, not far from the airport, it's hard to miss it and I'm sure nobody really needs that option). Needless to say we didn't take that option. However, she managed to sell us an additional insurance in case the car was stolen (it wasn't). She then tried to sell an additional insurance for every little damage that might occur. We didn't take the full package, which led her to look over to her colleague and say something in an uncomfortable tone in Croatian.
The car was good, we got the navigation system as we ordered (although not the built in one and we were glad to check before starting our journey, as they needed to give us a mobile one only after we complaint that the built in nav. didn't work).
Since we've had a rough start, I was afraid upon giving the car back - but it was a much more relaxed experience. The young man who handled the check upon returning the car had a calm attitude and was very laid back.
Don't know if I'd rent again. Altogether it cost us about 500 EUR for a week, which I consider a bit pricey.