Pros
You will gain experience working with various sponsors, training is adequate, and you will have support from other CASs.
Cons
Your experience in the role is greatly dependent on your manager. Some study teams have experienced STMs and CTMs who are knowledgeable and will share that knowledge. Other STMs and CTMs are new, run away from questions, and leave you holding the bag. Some ask you questions that they should know the answer to while getting paid salary grades above you. There is also unbalanced workloads. Depending on your manager and assigned resource analyst, some people have to be allocated at least 97% or higher (sometimes being asked to go over 100%) while others float by 70-85% allocated. Some STM's have an attitude that everything had to be done yesterday, which quickly gets old. Also, you will have to babysit sites who don’t know how to fill out basic documentation.