In no particular order:
Gold Treatment
I love my local HLE
Hours (they are there on Sunday, Enterprise is not for instance locally)
Cost
Decent Vehicles
My personal rentals are usually split between National and Hertz based pretty much on which one saves me the most money on that rental.
I'll occasionally use Enterprise if I need a cargo van, but it takes forever waiting in their office, then the walk around the car, etc, and not being open on Sunday means any weekend rental is a two day rental.