At the MA level in Taiwan as a prospective teacher, I don’t think it would matter much which one you chose. That’s if your ultimate goal is to get a university job in Taiwan. You’ll find that the choices are not as broad as they were, say, 10 years ago. Nowadays even the schools waaay out in the middle of nowhere would like a Ph.D.
As far as continuing your education someday abroad, or getting a job outside of Taiwan as a teacher, I can’t speak for other places, but in the US it’s extremely difficult to even get an interview if you don’t have a Ph.D. – NO MATTER what the ad says! (I’m talking about community college and university positions). Be careful when choosing a school as many Taiwanese school MAs might not impress a foreign university if you decide to go on for a Ph.D later in life.
Long story short: it’s a requirement but don’t count on getting teaching jobs on the strength of your MA. There are too many Ph.Ds kicking around without jobs these days. But as a native speaker in Taiwan you’ve got one up on many so it’s not a totally lost cause. The trick is to get hired full time as adjunct positions don’t really do much for you financially.