We had a very good experience with Sicily by Car in May 2017.
Checkin was very quick and easy and I had no hard sell when I produced my LCW cover document.
When we got to our car we found that our 2 cases would fit in the boot - it was an intermediate car with supposedly room for 5 passengers and 3 cases. The person at the rental returns said that all the cars had the same boot space and we'd have to move up a group ie pay more. However, we returned to the main office and the person there was much more helpful and took a number of keys for different cars and went with us to try and see which would be ok. Luckily our cases fitted in the first one we tried - a Citroen Cactus and so we changed to that, the paper work only taking about 5 minutes. The only downside was that the car wasnt clean outside and only had 3/4 fuel.
On our return, the checkin was very quick and easy and there was no quibble over the fuel which was just over 3/4 full.
Well done Sicily by Car we'd definitely use them again.