I'm currently teaching in Thailand. Based on my experience in a government school you can expect some of the following; class sizes of 50, often no curriculum with difficult working conditions. Classes have no air-con etc. Having said that, I loved every minute! Students are very respectful (on the whole) and you do appreciate your efforts. Also so kind hearted and friendly.
I've heard S.Korea is one of the best, for working conditions, saving potential and benefit packages. Class sizes are small, a curriculum is provided and everything is in place ready for you to go. Much similar to Japan, however living expenses are more here.
I hope you find the job that suits you best! If you need any more advice, drop me an email.