All i all it was a good experience. I worried over the reviews bit decided tonsave the $100 and give them a try. Checkin was a breeze and it took very little time to get the brand new Hyundai out of the garage. I expected a tiny car but ours was a 4 door.
The only annoyance was the customer service around not buying their insurance. Most places push a little and the Sixt employee seemed disgruntled by it. They said that since we didn't buy coverage they wouldn't dova walk around of the car with us. What that tells me is that their insurance is more profit center than protection. As it probably is for most companies and yet I have never had the unfriendly customer service to go with it.
Finally, I left my hat in the car and tried to use the lost and found online but their form requires a rental agreement number which they don't provide anywhere. I emailed customer service and never heard back.
In the end I believe it was a good deal overall. I don't really expect there to be good service for that low price. It was quick and no fuss which I like.