Pros
There are few other jobs that will expose you to the sights and experiences afforded by the US Secret Service. It is a truly unique organization. The pay scale is excellent in the law enforcement field. Special Agents are among the hardest working, detail oriented people I have ever known.
Cons
The US Secret Service does not value its employees. Agents and officers are required to work weeks on end without days off. Special Agents in Charge (SAIC's) have full control of agents' careers and have no external motivation to develop or advance their subordinates. Middle managers regularly ignore and abuse payroll rules in order to impress HQ and gain that next promotion. In all, there is very little oversight from Washington. Field Office supervisors have carte blanche to treat employees in any way they see fit. The more an individual "looks" the part of a Special Agent, the better chances their career will be enhanced with high-level assignments, foreign trips and less grunt-work (i.e. post standing).