Pros
Training for the next job. Don't let the "six figures in six years" motto fool you. If you can stick with company for 2-3 years it will prove you have the work ethic to make it in other sales jobs. If you are willing to work your butt off for the little Enterprise will pay you, you will work even harder for the 30%- 60% commission you will make in your next sales job!
Cons
The "six figures" jobs have long since been filled. Ever since the recession of 2009 they have eliminated most of their "Level 3" (Area Manager's) and "Level 4" (Regional Rental Manager) roles. What this means for you (as the person who comes in at the same position everyone else in this company entered in at), there is a traffic jam of people in "Level 2" (Branch Manager). I started working with the company in 2007, when the recession hit, everyone took pay cuts, but very few were laid off, even the CEO (Andy Taylor, the son of the founder) didn't even pay himself. This gave me such a drive that my job security was sound. What I didn't understand is that this company thrives on recessions. The company realized (which I'm sure they've learned from previous recessions) that they will treat this as another cycle in economy. The more experienced "Level 2" employees will be moved to smaller branches (smaller branches means less commissions since there is less inevntory so your large commission percentage isn't multiplied by much), and the will put brand new "Level 2" employees at their biggest and busiest branches with small commission percentages with large ineventory (multiplier factor). The new employees will burn themselves out within a year (lookup the average time an employee stays with this company) and the more experienced employees will stick around till they are fully vested and leave. You literally have a better chance starting your own business and becoming successful than you do becoming a "Level 3" or higher employee at at Enterprise, National, or Alamo Rental Car.