We have rented a Suburban from LessPay for June 9-16. I am told I need to pay the entire amount [1500 pesos a day] when I pick it up. Is this the norm? I'm worried if something goes wrong with it, I've already paid and they have no incentive to fix it.

I just rented a car in Europe and they held 1,200 euros against my credit card against a 914 euro bill. While I did not pay the amount, it was a hold on my credit card. If you are talking cash, that is another matter.

We always use a cc, not only for the added insurance but for practicality. (And speaking of insurance, full coverage with zero liability is the way to go in Mexico.) I don't think you can rent a car anywhere without collateral. We enjoy driving the south and east coast, be sure to stop at the Bob Marley Bar on the south to, amazing views there.
http://bobmarleybar.com

Sorry Desdemona, just realized you were there last month. How did your trip go?

No way would I pay cash up front! Not in a million years.
Only with a major credit card. Cap one with no fees and insurance included.

Insurance may be included but you're taking a risk of spending time at the jailhouse if involved in an accident. We are also covered by cc as well as our auto insurance and although I have declined the extra insurance in the past no longer.

Thanks for the replies, but yes, they were too late. I ended up cancelling that reservation and went with Fiesta. They were fantastic! Unfortunately, we were there during the tropical depression, Bill. It rained us out many days, but we managed. We did a 'restaurant crawl' one of those rainy days where we would all have drinks and order one entree to share. Then on to the next. That way we got to try many of the places that had been recommended. Fun way to make the best of a non-beach day!