Caveat wrote:

> Policia are not all corrupt, 

I dispute that a bit.  We rented a car out of Merida to go south, and 
were pulled over in Uman.  They claimed I ran a red light, which was 
bullshit.  Ended up paying their damn mordida.

Otherwise, we had no problems at all, and I would still recommend 
renting in the Yucatan.  Just be careful going through Uman.  :-)