At the present time, the car rental company six t has the best rates for my arrival date at MCO. It's not on site so I am a bit leary and I don't ever rent cars. Anyone have any opinions to offer? Thanks.
To be honest, SIXT isn't very large in the US compared to Europe (they are more known in Europe). I have not really seen much talk about them on the forums here either.
I'd try FlyerTalk.com, they have a subforum specifically for this company:
EDIT: The reason I don't think anyone has heard of them is that they just opened their office/facility in Orlando on January 16. This is only the fourth facility that they have in the US.