Pros
It is one of the largest handset makers in the world and they do make some good products. It certainly is a plus on your resume. You can meet and work with some smart people in Korea.
Cons
The upper management know very little about software. There is lot of politics and there are many incompetent managers. The project schedule is always hard to achieve thus making you work long hours, weekends and holidays. You do not have a personal life since you basically live at the company. If you are a foreign employee working in Korea, you won't get a lot of action even if you speak good Korean. The basic salary is below average. You get paid above average if your division makes lots of profit. (e.g. Mobile Communication Division) You can get up to 50% of your annual salary. If your division do not profit, you will be very disappointed. (If they pay you a lot, then there is certainly a good reason behind it.) Once in a while you can find people die possibly due to pressure, stress and too much work. The company tries to keep things very quiet about this. They make money ripping off small Korean companies and part suppliers. They won't ever make something innovative like the iPhone.