Pros
The breadth of projects available and the pockets of talent and ideas available can be amazing if you know where to look and are willing to do the work to cut across divisional boundaries to make the connections. The opportunities to move across a wide range of products and job roles within the company are quite good. I think it would be quite easy to spend an entire working career within KT by moving between job functions and product groups. International exposure both to external customers and internal co-workers / support groups, is part of the day-to-day routine. If you like exposure to a broad range of cultures and places, it's hard to beat KT.
Cons
Firefighting is rewarded. Preventing fires is not. This leads to a lot of difficult, demoralizing diversion from core development activities. Innovation outside of certain narrow corridors is very very hard. The company had become big enough that it squashes ideas that don't immediately fall into a certain well worn path.