Pros
Good technology, good learning chances. Good benefits IF you end up as regular employee instead of contracting. Great if you speak Korean. Diverse culture.
Cons
Most positions are contracting through other agencies, lots of cheap Visa labor. A Korean's word is worth that of 10 Americans - so don't even try to persuade things to go the way you think is right. Crazy level of approvals required for anything. Without a Doctor's note you cannot get a non-standard keyboard or mouse - and just forget about wireless. Must get approval every year for every exception, like being allowed to use USB ports (and it might take a week, or a month to go through the system). If you don't force the work-life balance, they will walk all over you. Some managers allow flexibility, but it's rare. Goal seems to be: Be #2 - copy innovation rather than create it, but then try to be more profitable with it. Works well, but not the best for the people.