Pros
SEIU has an amazing mission to help working people get a fair shot in our economy that's rigged for the wealthy and top 1%. The benefits are top notch - it's very difficult to find the pay, healthcare benefits, time off, and pension at other social justice or nonprofit organizations. The people who work at SEIU are amazing and some of the best, talented people in the labor movement. It's truly a privilege to have worked there.
Cons
There is a serious retention issue at SEIU. Really good people are leaving the Union who have a lot of talent and dedication to SEIU but just can't handle the day-to-day stuff. If you're not working on a priority campaign or have a manager that will look out for you and provide opportunities, it can be extremely difficult to build a career that is meaningful and fulfilling at SEIU. A lot of the managers have no business being managers and actively refuse to put the time and effort into being good managers. Nothing is worse than having a terrible manager that everyone knows is a terrible manager but is still there for no reason at all.