A great first job to have, but not a place for the ambitious to build a career
Pros
If you have no experience, Enterprise will train you from the ground up. Employees learn hands-on about all the fundamentals of business, and the learning curve is steep. They expect a lot from their employees, so they really have to step up. They only promote from within, so it's a great place to get "management" experience. Training and development are a top priority there, so you can expect to receive attention from your managers in this area. The managers are paid based on their performance matricies, part of this mix is getting an employee promoted, so they really are vested in the success of their employees, their compensation depends on it.
Cons
There is a certain point where being ambitious and smart means you will grow out of the company. They do not support employees furthering their education and do not provide or support continuing education. They say all the training that you need is provided internally, which is true to an extent, but it means that many managers operate with blinders on because all their learning has been within a vacuum. Employees become so engrossed in the company, they are very detached from the rest of the world, which is dangerous these days. The pay is very low. They use the carrot dangling incentive technique, which is effective to an extent. But to an employee using it as a training ground, I recommend continuing to build a resume that will be meaningful to somebody outside the company and keep it in perspective how much you are worth in the marketplace. I know a few people who were so burnt out from the 60+ hour workweeks and low pay that they took the first outside offer they were given, even though it wasn't really a good offer and they could have done better.