Great if you get a career position and don't abuse the privileges. You generally start out as a PSE which doesn't come with any privileges or benefits. The pay is good but the environment generally is horrible, especially when you have more than one regular clerk who make life difficult because they are unionized.
The USPS is a honorable job who’s purpose is to serve the community. The benefits are excellent for full time workers. However the assistants ( or part timers) do not qualify for disability, unemployment or sick leave.