Pros:
- video lectures are generally pretty polished, and include animations and other visual aids to help build intuition
- the course material is mostly high quality. this is the same material that on-site graduate students are presented, and the graded projects are challenging.
- there is opportunity to interact with other students and TAs: online message board, video office hours, unofficial Slack, etc.
- flexible enough to schedule around a full-time job
- inexpensive compared to in-person programs (the entire program with 10 courses is $7-$8k)
Cons:
- quality of materials, TAs, and organization can vary from course to course and term to term
- harder to build relationships / network than in-person programs
- it's course-based by default. you can pursue a research-based degree but it's nonstandard.
[0]: https://en.wikipedia.org/wiki/Georgia_Tech_Online_Master_of_...