Pros
Experienced, bright and down-to-earth colleagues, freedom to shape your job and work hours if you are delivering numbers and quality. Consultants tend to have a nice mix of confidence and humility. Access to Gartner research great asset for new consultants. Very good pay if you are successful, great pay if you exceed expectations. If you can deliver great quality on schedule, you will be rewarded and have high work-life balance. Fixed-price/fixed-scope engagements reward those who can deliver high quality reports fast.
Cons
None, really...just be aware of the requirements. Hitting utilization targets is very important almost from day one. Can be tough for those who have not developed an internal reputation yet. Must be prepared to travel if necessary to hit numbers which can be difficult in some markets (and relatively easy in others). As lower margin business (compared to Research) in a public company, financial requirements can result in high pressure on consultants to work extra hours to secure both client satisfaction and corporate profit.