Pros
You get a lot of hands on experience as well playing with a lot of automation toys which can be a break from typical office cubical world. The training they give in the beginning is great too.
Cons
Field Service Engineering position is the lowest engineering position at Rockwell. They hire Engineering Technology majors, even technicians with enough experience to do the job. Basically you don't need a real engineering degree to do the job. Sales people (& everyone else at Rockwell) consider Field Service Engineers replaceable and therefore try to abuse them as much as they can. Also one note about sales engineers, they have ZERO technical knowledge about what they sell. So they could sell an automation product claiming it will cure cancer and you have to go to customer and actually do it.