Pros
The work environment is relatively positive and easy going, the management can be pressuring but at the same time they are aware that the senior position can be exhausting, so they rarely blame things on you. (That is my personal experience). Working there can give you a great technical base to step on, so that you can move on to better paid positions elsewhere.
Cons
Unclear responsibilities for the senior position. Many different responsibilities at once: workflow, escalations, assisting junior agents, monitoring completion of tickets, performing quality checks on juniors, participation in meetings, taking calls occasionally, performing additional tasks on the spot. Unfortunately, all of that is expected to be done swiftly and with great quality, but you never have time for all of those at once. The salaries are close to, but still below average.