Pros
The salary even as consultants is very competitive; there is flexibility depending on the type of level you work in; as staff the health and benefits package is supposed to be amazing; you work in development and get to work with top government officials; depending on your TORs, you will have the opportunity to travel and see implementation on the ground. Work can be very interesting and have an impact in the countries you work on.
Cons
Management is not strategic or transparent about hiring/continuing contracts; contract extensions are done by days (20 or 60 at a time); as consultant there is no job security; no benefits or support from the central administration; no work space or resources; as an STC max amount of days in a fiscal year are 150; ETCs cannot be renewed past 2 years; JPAs have to leave the back for 2 years after 2 years of work. The WB is a big system, project design can take from 6 months to a year, and can slow down implementation with bureaucratic processes. Depending on your Project Manager, work might be interesting or not.