We rented from Enterprise Rent-A-Car this past May. I rent vehicles for work all the time, and am able to use my corporate rate even from personal rentals. You may want to check and see if your employer has a contract set up.
The way it worked out on our trip was that we had reserved a specific car (2010 Ford Taurus) since we were thinking about buying one and we wanted to get the feel for it on a long trip. However, when I arrived at our local branch they were renting it to another individual! So since the only thing they had left on their lot were mini-vans (only two of us in the car) - they sent me to another local branch where they upgraded us to a 'luxury' car for the price of a mid-size vehicle (we ended up saving almost $300.00 over the car we had reserved) but ended up driving a Chrysler 300 - which yeah - they are 'cool' looking cars - however I really don't like anything made by Dodge, Chrysler, or Jeep - as they drive like something won from a claw machine!
But it was OK for us.
BUT - I do not recommend Enterprise - their cars are not kept in good repair - and have even been forced to rent vehicles with repair issues (like warped brake rotors, bald tires, expired oil changes, very bad smoke smell, very dirty, and even missing body trim pieces and peeling paint.)
From all that I have read, Hertz,
Avis, and National are some of the better rental companies.