I've used them 2 years.
Displays multiple providers' options/rates (saving much time) & "Total Cost" for complete rental period*.
1) (516) phone # invalid.
2) Can NEVER talk with a human**.
3) There's an expensive & un-waiverable, daily-based, Panamanian insurance charge. IT MORE THAN DOUBLES THE DAILY RATE & ISN'T INCLUDED IN "Total Cost". Notified CarRentals on 2 occasions. However, & honestly, since it cannot be waived, it's a charge that must be paid in Panama (maybe elsewhere). There may be a disclaimer somewhere in their web site which deals with this. But, if there is, who's going to bother looking for it & where would one find it?
I would have rated CarRentals 5 stars instead of 4, but I feel the noted "Cons" are worthy of a downgrade.
* Unwaiverable Panamanian insurance is NOT INCLUDED in "Total Cost".
**A recent error in their reservation system caused me much grief. I'm a retired mainframe-computer programmer, therefore the details.
Dollar Rentacar 800# (my selected rental Provider) Customer Service was dismal. His "pat answer" was to cancel the reservation & re-book it (resulting in the same error, TWICE). One other suggestion was to reserve the rental incorrectly and then have the issue resolved upon dropping-off the car. Unacceptable.
He wouldn't "take this to a higher level" nor report the problem to the appropriate entity. He simply continued to be robotic with his "solution".
Within a "Contact Us" email to CarRentals, I thoroughly documented the problem. Step-by-step (13 of them), each process, & identified where the error appeared. I submitted my findings. Asked for resolution.
1st reply sounded like Dollar's.
3 more emails before resolution (acknowledgement of program problem, specifically related to Dollar/Panama & an apology for the inconvenience - no renumeration) with one reply indicating there is no Customer Support telephone number as it's an "online booking system" (which they believe is perfect).
Pros: More/less "One Stop Shopping" with competitive, or better, rates.
Cons: Misleading "Total Cost" in some circumstances