It's difficult to give advice without knowing your background and expectations, but here are some things you need to consider when choosing a course:
You've mentioned a large range of cities in which you can study. Have you considered the cost of living while you are there and practical issues such as accomodation and travel? Your own personal preferences for cultures and climates should be considered too. For example, can you work well in extreme heat?
Schools that are looking for teachers can advertise at the training centre where you do your TEFL course. This is something you can ask about before you register. Do they have posts advertised just for the immediate area or are the ads more far-reaching? Will they be able to help you find work in the country where you plan to work?
As for job prospects, with a good grade CELTA you should get a job easily. In the end, it's up to you how good that job is.
Some training centres require participants to have a university degree before they can register on a TEFL course, others waive the necessity if you can prove equivalent standing. This is obviously an important consideration if you don't have a degree.
You can also consider your own personal preferences for studying. Ask somebody at the training centre how the courses are organised. Is there a lot of work in small groups? or are the sessions mostly led by the trainer? What is the balance between theory and practical work? On the level of personal preferences, how intensive is the course?
You can also check my reply to Tim Dyke and the FAQ's at the following link:
I hope you enjoy your course, whatever you decide to do.