Pros
As a nonprofit and nonpublic organization, there is a genuine desire to serve customers. Profits are important but the focus is on enhancing returns to participants, not stockholders. Pay is good generally, except in low level back office and call center functions. Benefits are also good and the work environment is comfortable.
Cons
The pay for performance mantra doesn't really work. Just like most companies, senior managers have their favorite employees who always get rated highly and the best bonuses. The job posting system helps low level staff move around the company but for higher level jobs it reverts to relationships, inside track recommendations and high pressure to favor minorities (postings are often done for policy/procedural purposes rather than to objectively consider a broad range of candidates).