Being a Hertz convert, I still feel uneasy about not getting a pre-printed contract, but so long as the gate agent doesn't say anything, it's been good. I usually check the day of to make sure my reservation details are correct. Receipt of course printed when you return.

Then once you arrive, pick any car you want!

Very helpful for me:
http://www.flyertalk.com/forum/16618521-post1.html