Dollar or National car rental?

[Rroo]

Can anyone list the differences between these two car rental companies or name why one may be better than the other?
Does anyone know if the have any cancellation penalties or charges? I was thinking of maybe booking both and cancelling the one I decide not to go with.

Thanks!

 

[Bob P]

There are definitely no cancellation penalties. Rental car companies do not take your credit card number when you book.

Personally, I have never found a difference among car rental companies. I always go with the best price.