Assuming  you  mean the distance learning  course, much  depends on  your personal requirement. Some people do  a TESOL course because they want  to  learn how to  teach, others do one because they  want  a paper qualificatiobn  to get a teaching  job. The LTTC course will provide a great deal of excellent teaching  theory from a linguisitics angle - there is some fairly difficult IPA stuff to get through, and it's stuff you'll never need to know or use. The real test of the LTTC course is of your capacity to  write assignments based on the course material and further reading. Where the course fails, is in its total lack of preparing one for the real classroom situation, it  rather leaves one in the deep end. For people with  a natural talent for communication skills it is a worthwhile solution to  obtaining  a qualification.
If you  need to  gain  confidence for the practical side of teaching, which is perhaps of more value, then you  should opt  for a face-to-face course.
If it's theory and linguistics that interest you more, I  can recommend the LTTC course.