Pros
Yes, you can move up quickly...but that's only to keep you from getting burnt out. They do allow for internal position changes, which is nice. A lot of the sales staff will transition to success or management because of this.
Cons
Extremely long hours (8:30am to 6pm minimum and usually work through lunch). Low base pay and no reimbursement for using personal cell phones. No 401k match. Extremely high turnover. The most tenured employees (except for the first 10 or 15) have been with the company for less than 2 years. And there are only a handful of them. Terrible work-life balance because of the high stress and long hours. Unrealistic goals and you only get commission if you hit above a certain percent of your goal, not for each sale. There are much better places to work and you're better off taking a job elsewhere.