Pros
I've been in sales at Gartner for over seven years, in different roles in different countries. So you get great opportunities to learn, and if you do well, you get opportunities to advance your career. This is a company that GREATLY values collaboration and best practice sharing - people really want to learn from the best, no matter where that comes from. And you get to work with really intelligent people: your clients, your peers, and the Analysts - you get to work on difficult/tricky challenges with smart people, and you can positively impact a company's future, people's careers, etc. It's a job with a lot of responsibility, but you get tons of training and mentoring to make sure you can do great work. If you're self-motivated, driven, curious, and want to do something valuable, I would highly recommend you consider a sales role in Gartner.
Cons
Sometimes you really have to know who to reach out to in order to get some things done. But that's also ok, it means people still make a difference in the 21st Century.