It's not how they maintain the car.

It's about how the car was used.

Let's say people push engine to redline all the time, how Hertz can do about it?

If it's only 1 year old, oil change is probably all they do. Hertz won't change oil early. They just follow manufacture's schedule.

You don't need to have someone check the car as dealership is required to inspect the car and fix any found problem before it becomes CPO. They also have to put new tires usually.

You will have remaining factory warranty plus extended warranty. If you have problems later on, you can always come back and have them fix the problem.

You can always negotiate the price. You can use http://www.vmrintl.com for price reference.