Who would you prefer to teach - young kids, teenagers or adults?
Some students are eager, some are recalcitrant; some students are delightful, some are dire. However, the good news is that to a large extent the kind of student you get is related to the kind of teacher you are.
Why they are so much more rewarding than kids
If anyone was coming to Thailand to teach I would recommend they teach adults as it will be a much more rewarding experience for them. You will also have lower stress levels and enjoy talking about a range of topics with students who, on the whole, want to be there.