Recruiters
Are people too
Here's a list of people and companies that I worked with and thought were good. They're in alphabetical order.
I worked for Topia at the Juk Jeon campus and loved it. The students were very smart, they enjoyed learning, the teachers were concerned about the students and about each other, my bosses were great to work for and great to drink with. I met lots of people from the other campuses and I can tell you they're great people, too, but I haven't met everyone and I don't know their students. Now on to how recruiting works.
Many people don't know how the recruiting works with teaching English overseas, and it will help the process some if you do know. First thing to know is that the recruiters get paid for every person they place with a school, so they are going to work pretty hard to get you a school you like. Just tell them what you want and do not want and they'll do their best. However, most recruiters work for a recruiting company who has contracts or agreements with certain schools in certain areas. Let's say you're working with ASK and you want to teach in some smaller town like Uiryeong. Well, ASK might not have any contacts in that city, but they may have some around that area. If you want to teach in a bigger city like Seoul or Busan, then odds are every recruiting company will have some contacts there, so no worries.
If you have very specific desires and won't budge, it'll be more difficult to place you. If you only want to work with high school students, then good luck because for some reason there just aren't many high school positions. There are tons of kindergarten and elementary positions, less middle school, and even fewer high school, college and adult positions. I finally compromised and went with an elementary position, but they're far smarter than I ever imagined, and they actually want to learn at that level. The older they get the more jaded they become to school, since they attend 6 days/week, up to 12 hours/day.
Recruiters really want to place you because that's how they get paid, so they'll sometimes try to stick you with a job that is only partly what you want. If you can compromise, do it, but if not then be prepared to wait a while until you find something you like.
Something I did when I first started, and regretted it, was I put my resume on dozens of websites and then I got hundreds of emails from numerous recruiters and companies. They don't tend to appreciate that, as it turns out. They want you to work with only them because if they're working hard to place you, then someone else gets you placed, they've just wasted time they could've spent with someone else.
P.S. I have a free 30-day pass to http://www.jobs4teachers.org/. I never used them b/c you have to pay, but they might be good. Contact me if you're interested. First person who emails me gets it.