Pros
Gallup is most widely known for the survey resarch or the Gallup Poll, but in the last 20 years has grown into a widely known Performance Management Consulting firm. Those that speak only about the survey part are most likely individuals that worked primarily in the interviewing centers. The Consulting business works with companies to help them focus on the engagement of both their employees and customers. As we all know, a great customer experience usually happens due to happy and engaged employees. Gallup works to help companies select and hire, and then develop and track employee engagement and customer loyalty. Gallup has over 30 years of quantative and qualitative research in studing excellence in roles. Additionally, Gallup is the leading research company when it comes to emotional economics and well being. I'd encourage you to learn more for yourself at www.gallup.com. Gallup is making the world a better place each and every day by focusing on what matters most -- people.
Cons
It is true that Gallup is a tough company to get in to. It's not about asking the question of "could I do that job?" it is asking the question, "will I be set up for excellence within the role?" The traditional corporate model of moving "up the corporate ladder" does not necessiarly hold true at Gallup. Gallup hires talented people into a role with the premise that they will stick with that role for quite awhile. HOWEVER that does not mean that there are not systems built in for both personal and professional growth - because there are. Why would you take an excellent manager out of his or her role and make them a sales person when their talent is all about managing people? There IS opportunity for personal and professional growth - it's just not the "change to a new role to move up the ladder" model.