I was hesitant to rent from sixt with all the negative reviews, but they had the car I wanted for the price I wanted, so I bit the bullet.
One day before I was picking up the car, I was told they didn't have it, but would get me into something similar. I agreed and when I showed up the next day, it was ready to go.
I was satisfied, I guess. It did what I needed, and was good on fuel. I got the extra insurance, just in case but didn't get the additional country insurance. I ended up going over the border anyway, but didn't have any issues.
Car was returned and they verified all was good. I suppose I will use sixt again in the future.