Pros
Working with the brightest and best. Clients are wide ranging and always have interesting problems ("challenges") that need solving. Gartner resources (research, toolkits, best practices, analyst calls, events, client communities, etc.) are world-class and provide actionable insights for real-world problem solving.
Cons
For a Partner role, your first year in you receive a peer coach and as much attention from your Manager as you wish. The second year on you continue to be coached and developed by your Manager, however Gartner is a performanced based company. Potential and baseline skills are not reward. Rather, you are expected to delivery such compelling value to each of your members in your portfolio that you are asked to stay-on for another year (member renews your service). Advisory Partners sustain value (keep the customer base), rather open new business/accounts.