I applied and went through this process on kind of a whim and a gut feeling, and the next thing I knew I was on a plane to Korea.
Adventure Teaching made this easy. They walk you through everything from the beginning so you know how the application process works and the deadlines and such. It might be a bit too drawn out, but it's very clear with little confusion. They have excellent information about the country and your new personal and social life there - the info itself is personal and delivered by knowledgeable and friendly staff that I felt very comfortable calling at any time. Plus they were always very quick with responding to emails and would answer ANY questions you had about living in this foreign country, no matter how stupid I thought I sounded.
By far the best things about this company was their personable staff, injecting initial confidence and information in a quick, friendly (and user friendly) way, and smoothing out the application process for you.
Their fault to me was that they were a bit pushy for me to sign a contract, saying it was the best offer I was going to get, and their tone switched a bit. I felt like they should have been more understanding considering that this was a big decision for me; however, I recognize that they probably had a strict deadline and for them I was already hooked anyways.
Everything went exactly as planned once I arrived in the country, just like they said it would. I just followed their emailed instructions about where to go from the airport and it was really easy.
I met the greatest people in Korea. I can't begin to describe the people, the food, the hiking, and the experiences there. I miss it so. It is so easy for an open minded foreigner to live there and be involved. The key for me was meeting others in an expat community. I joined a hockey league and got lucky meeting people on bar crawls and in the street. Your social life and confidence will be the best it's ever been. Here's a tip: say YES to EVERYTHING in your first month. It will set the tone for your whole year and you will build great relationships. It's draining, new, and so damn exciting, I'm excited for you!!!
One more fault was that once I was there, communication from Adventure Teaching pretty much stopped, save for a two month check in. I understand that some people get lonely easily while on this adventure, and so I feel like AT could give better recommendations on foreigner friendly clubs, areas, events and so-on. I'm sure that if I would have emailed and asked them, they could have given me some recommendations, but I didn't need to because I met so many people in the first month.
As I see it, their job is to find you a job and prepare you for Korea, it's up to you to do your own research about the various contracts and schools that will be offered to you, while including their (perhaps hasty) opinions. They excel in getting you prepared for your new life there, and for making the lengthy and confusing application process as easy for you (a beginner) as possible. They could be more helpful once you're in the country (but I never needed it so...) and they could give you better information about the schools you're placed in, as well as giving you a few contact options once you land - preferably your head foreign teacher - just in case anything goes awry. Most bad experiences I've heard from are where someone's co-workers or bosses are terrible, and that's hard to gauge until you've been there a few weeks.