Money is great, but your just a number.... remember that.
Pros
The starting salaries are fantastic for USPS depending on what position you choose. No education, no experience, no problem most of the time once you past the test. If you love overtime, most likely your going to get it.
Cons
If your hired as a PSE your going to be worked to hell, I worked for three years almost solid 50-60 hour weeks. That was a midnight schedule with no weekends or holidays. CCA of RCA positions are not much better, it really depends on the office you choose. Sometimes you could convert to fulltime in a year or two, while the smaller offices can go for 10 years before you become a career. As a temporary/relief employee you can be denied days off, call-ins are mandatory and hours are never set. It is rough mentally and physically, be prepared to change your life around the post office. Oh yeah and Christmas season will make or break you as an employee, I have seen 75 hour weeks towards the end.