I've been renting regularly from Fox the past few months (I go to LAS once a month) because they're cheapest. Other than that you have to take two shuttles, which is true of all the companies not located in the car rental facility, I have nothing bad to say about them. The second shuttle that they operate is pretty efficient. Of course if you are going to be exceptionally tight on time on your return you wouldn't want to use them.
My main reason for posting is to advise that their weekly rates are often cheaper than six or even five days. And of course that spares you having to worry about the grace period, if that's going to be an issue.
I've also found that sometimes, close to the trip, the rates go down. Of course, sometimes close to the trip they're sold out!
Last month I rented from them for 10 days for $253 all-in. That would have been an excellent price two years ago; given current car rental rates it's freaking awesome. I did have a kerfuffle with them where they charged me for gas, when I had told them I'd just return the car full (which I did) but they refunded the gas charge pretty promptly when I wrote to them about it.