SO the pros ... the best rates out there.
The cons ... IF you can brave the wait (always the LONGEST lines at the rental car terminal by a factor of 5-10), and IF you don't smack the agent in the face for speaking so condescendingly to you in the guise of selling you an upgrade MULTIPLE times (told a couple next to me "I guess you must be ok with how small and tiny this compact car is ... " after trying no fewer than 4 times to get them to upgrade) - an ... and IF you are OK with a car that may or may not have been maintained or cleaned the best ... you will likely be OK with Fox.
I had rented from Fox 2 years ago and had the same experience. I gave them a second chance thinking they had had some time to get their act together. Not so much.
Know what you are getting into, plan accordingly ...