Avantages
The University and faculty provide very good research-friendly atmosphere. Post Doc salaries are negotiable unless government funded fellowships are availed. Foreign PhD students are taught basic Korean language (compulsory).
Inconvénients
Aliens/foreign researchers/faculty can either do research or teaching but not both. Work-life balance (if one wishes to take family) is at stake in most laboratories. However, with the serious research, you can expect long working hours some days of the week....but every day is a little too much. Except for PIs Post-Docs or senior researchers would find trouble communicating in English with most students, colleagues or general people outside the office. It's hard to find time to learn the language in such busy schedule.