Pros
At the end of the day, you work for your country. Military service is a calling and is not necessarily for everyone. As an electronics professional, I get great job satisfaction in what I do and the training is easily transferrable to the civilian sector. They've paid for my BS degree and will no doubt help me once I get out. They will also pay for any JOB RELATED professional certifications. Time off is easily granted as long as it doesnt interfere with duties. Not to beat up the cliche, but you will get out of it the amount you put in to it.
Cons
A large majority of managers are simply promoted based on "time in paygrade" or being in the right place at the right time. Interviews are never conducted so you will always end up dealing with managers who have little to no people skills, communication skills, or even managerial abilities. Its pretty sad. Also, keep in mind this is federal service so you have to be ready to take the beauocracy element of the job. Meaningless training, clicking through manatory powerpoint slides and taking a meaningless test, signing the meaningless roster to note you've received this meaningless training, and the whole time, losing countless manhours that could've been applied elsewhere.