The likelihood is that if you need to check Glassdoor for a review on any sales role you are not a confident sales-person or worthy reader of people. If you are not a talented sales-person (closely related to confidence) you will not last, and nor should you. Your job is to sell today, not idle around on the phone and "promise tomorrow". In order to sell and make your fortune requires hard work so its not easy street here; don't expect it to have it all drop in your lap.
I'm assuming you got this far as you want to work here? Milk it for all you can and be a hero.
Obviously I cannot say much for other departments, but they all seem pretty happy to me.