MA in TESOL or MA in TEAP?

[Hanamex]

Hi!
I am wondering about the value of MA degrees....
I became an English teacher through circumstance. In the UK, I worked in academia, following completion of an MA and a PhD in subject areas not connected to English teaching. I completed my CELTA and now teach at a university in Mexico. However, I feel, as English teaching is now turning more into a career, it may be worth doing an MA related more specifically to teaching English. So if anyone has any advice, I'd be grateful to hear it!
1. First of all, in your view, is it worth doing an MA at all?!
2. Would it be better to pursue an MA in TESOL or an MA in Teaching English for Academic Purposes? (The latter interests me more, but is it too narrow?)
3. Anyone have any other advice?!
Looking forward to hearing views - thank you in advance!