Thanks a lot for the detailed info, codfishcandy!
I totally agree with you, I know that people usually just share the negative experiences with a company; however, I also measure the amount of negative reviews a company has compared to others. No here, but on TripAdvisor, I've read many awful stories that seemed legitimate, and also many people who seemed to defend the company with a brutal conflict of interest.
For example this thread [Edit: Sorry , the site does not sllow me to post links yet] : tripadvisor site /ShowTopic-g187275-i116-k4081322-o150-Don_t_rent_a_car_from_SIXT_that_s_all_I_am_saying-Germany dot html , even though the OP seems to be quite personal about his experience, you will find a user named nakagoli using on several posts messages such as "not sure why you are on a german forum." "however, accusing them of fraud is very serious." "t was you who broke the contract, and they were acting correctly." etc etc.
This is not to cause any stir, but to state the reason of why I'm worried about renting with Sixt, and this is why I ask for any decent and honest reviews if possible. Also I would like to know if there are any alternatives to companies like Sixt.
It's almost as if looking for impartial real reviews is impossible, and you are on your own when it comes to experiencing a company. Maybe that defeats the purpose of such sites, or maybe knowing ahead that a company will be poopy kinda takes the excitement from a trip? I don't know.
Thanks again for your review though, I guess that if I can't rent directly with Mercedes, I will go for Sixt and make sure to share my experience!
/iPod.