I would recommend to work in this environment for 1 year as it did develop excellent skills for working with the public and within a strict system of procedures. Having talked to and befriended a few staff members, it seems the burnout is around the 2 year mark. Having left 3 years ago, there is only 2 members of staff from a team of 60 that I know still work there when I started.
Plenty of work, mostly relaxed environment. Good benefits. Nature of the role means you work alone often, other days office is full. Good learning/training. Work load creeps up, but help is there if u ask. Staff nice, but do take advantage when you first start. You have to be assertive and strong.