Also SixTy were cheapest for me renting in Florida, SLK350 for 7 days was £190.
This has come up about 900 times in this thread now, and its misleading and gives people the impression they can rent Merc SLK's for 190 quid a week. They can't.
Sixt charge about that per week for a standard convertible - ie, Mustang or similar. Same as everyone else. You want a Merc convertible, right now for 1 week in low season it's circa £600.
What happened was that you got very lucky presumably because they didnt have anything else to give you and could hardly upgrade you to a mini-van, so you got a great deal.
It doesn't mean that £190 is the going rate for an SLK and all it does when you continually bring it up is mislead people