Pros
Lots of variety in the kinds of projects you work on, partly because of the variation in what sponsors are interested in from year to year. Good opportunities to team with people from different academic backgrounds and experiences. Historically a very collegial place to work.
Kontras
The variation in projects can be unsatisfying if you have a very focused area of interest, and the need to focus on sponsor questions won't appeal to someone with a strong advocacy perspective in most cases. RAND is still trying to figure out how to adapt to post-Covid changes in onsite work expectations. While mentoring is common, the decentralized structure makes it unlikely any you'll have a clear path for moving "up" as you would in more hierarchical companies.