Pros: We showed up in Loreto only to find out that there was not a car for us even though we had a reservation. We were one of 10 other travelers stuck in the same situation.
FYI Ace, Fox and Mexcar are all the same company. Do not rent from any of them!!
Cons: Mexican third-party liability insurance is not included in the fees and is required for Mexico, if you don't want to sit in jail while they figure out who is at fault in the accident. It is not covered by your credit card or your US insurance policies either. It is significantly more expensive than renting the car. overall though it was about $350 for a week renting a Volkswagen Jetta.
Car hire locations in Loreto (Baja California Sur):