Yet, I maintain, no one has really been there, because they simply are not you! Choosing a teaching location should not be taken lightly, but wherever you go, the experience that you have will be uniquely yours. When you arrive, you will see the place for the first time and through your own eyes. As you learn more about the culture, you will do so from the your own personal perspective, created by all your own past experiences. A city one person finds loud and irritating, you might find vibrant; students they find lazy, you might consider refreshingly laid-back!
Before I went to Costa Rica to teach, for example, I heard and read a lot of things—some good and some bad. On the bad side, I heard that the country was unsafe, there were no jobs for teachers and that it was overrun with gringos. As it turned out, this was not my impression at all, and I spent three fabulous years there feeling quite safe, working steadily and making plenty of local friends!
So my advice is to listen to seasoned traveler, Paul Theroux. Yes, do a bit of research, but remember, your experience abroad, whether or magical or tough or somewhere in between, will be just that—an experience. I guarantee no matter where you go, you will look back at teaching abroad as one of the best adventures of your life!