Pros
The world needs what the Bank does -- providing cutting edge development knowledge with at least enough money to get a seat at the table. Even staff in back-line functions (accounting, IT, etc.) can feel like they are contributing to achieving the Bank's mission. Very smart colleagues. Broadly multi-cultural -- you have to learn how to work with people from almost every country on earth.
Cons
In almost all functions and at almost all levels, it is a workaholic culture. Ten hour days are almost a minimum. Many managers have poor people and process management skills. Managing up is a common management style. Even the newly reduced span of control for managers in Lending Operations is far too wide. Matrix management (everyone has at least two bosses) has a lot of plusses and a lot of minuses. If you work in a country office, especially a small one, you may not have much face time with your manager and thus can be off the radar.