As a teaching assistant you're provided with the amount of tasks that must be completed by a certain deadline. You get to choose your working hours, and how you want to do the job. A great example is the tutorials. Tutorials are held at a certain time during the year, and you're responsible for that tutorial and its material. The questions and answers are provided to you, but it is at your complete discretion as to how the lesson is carried out.
Flexibility, Good pay.