Pros
Stable environment. matches 401k. does have a pension (but it's pretty much insignificant, at least for non-med professionals). the mission of the company is valid and valuable and it does feel good to provide healthcare to people. The company attempts, as much as it can, to be leading edge technology-wise and medical services-wise. As an employee and a patient of both them and another 10 times bigger HMO in California (whose initials are P and K, not necessarily in that order) they provide MUCH better healthcare, and that feels good.
Kontras
In the IS side of the business they're very stagnant, very stubborn, very slow and very lazy. As great as their healthcare is compared to other non-profit HMO's, etc., their IS development is poor, even with having tried to "invent" these past few years with their "Transformation Lab" and "Innovation Lab". Pay is only okay. Promotions and raises are hard to come buy considering how big an organization it is. They do like to nickel and dime a lot. Some of their mid-level IS management is really, truly terrible in enough different ways it would take too much time to list here. It comes from the sort of laid-back culture and is also partly why they don't like to pursue newer IS solutions.