Pros
Gartner is a great place to start your sales career. I would chose it again if I had to do it again. The amount you are micromanaged is heavily dependent on your manager - some are relaxed and let you work and others are the complete opposite. The work life balance is amazing. I feel my direct manager genuinely cares about me as a person.
Cons
They are pricing out middle market clients. With the business model, there are too many things out of your control. More so than other sales jobs. You are the service for your clients and have to show value for a product that is largely intangible ROI. You have to focus on service as an AE -sometimes so much that it can cannibalized your ability to grow accounts. Business development often hands off misaligned sales and then it becomes your responsibility to renew accounts that are doomed from the start. They pay external hires far more than they pay internal talent - this is a known problem which as a sales person is the largest con of them all.