I did 8 years as an MP and now I work as a Deputy. As an MP there are a lot of different "jobs" you can end up doing. As infantry you basically know what to expect.
I did just about every aspect of the job. I was first sent to Johnston Atoll and did physical security for chemical weapons, that was a 1 year stint without the wife (now ex).
Then I went to Ft Hood and was with the 1st Cav. There we did rotations of working the road and going to the field, although we were in the field most of the time. We did a rotation to Kuwait for 4 months and did combat support ops there.
When I got back I lucked out and got a job as a driver for the ADC (Assistant Division Commander) a 1 star general. That was fun and I got to see a whole other side of the Army. The schedule was brutal though as I was on the Bosses schedule and I worked mega hours. I did get to go to schools and they took really good care of me. We did a bunch of rotations to the NTC, JRTC and deployed to Bosnia for 9 months. In Bosnia I worked as driver for the PSD team and that was cool (no guard duty or other BS when you work with the command group)
I then became the CG's driver. That was also cool but the hours were hell. More NTC and time in the field.
At that point I was thinking about getting out but then found out there were MP's at Macdill AFB in Florida. I re-upped and got Macdill (thanks to the CG).
There I was on the CENTCOM PSD team working for Gen Franks, and what a blast that was. We were out of the country every month and I traveled around the world. I was there for the USS Cole bombing, overseas for 911- was on the only flight over the Atlantic since Lindberg since they closed the airspace; went into Afghanistan before ground troops, worked with the State Department at US Embassy's, did stuff with the CIA etc.....
I would highly recommend the MP field. You never know where your career can take you. Just be prepared for anything. You might spend you whole time in a field unit and hate life. You might spend you whole career and never get deployed. I had a E6 squad leader do 19 years and never go anywhere, only to get sent to Korea his last year (got to love DA).
I went through 1 wife but I don't blame the Army for that. Just be prepared for big changes with you and the MRS. You will change during basic, you will show up with a high and tight haircut and your wife will freak. You will use acronyms and driver her nuts. She will see base housing and loose her mind. Youre gone a lot and she has to hang with the other wifes (watch out!). Don't let her go the family support group (the family bitch group). You have to worry about Jody in the closet when your gone or get home (if you join you will learn what that means).
As long as you BOTH know there is a bunch of change ahead you should be ok.
Hope this helps, now that I look back at my time in, I really did enjoy my experience, even when I was sleeping in a fox hole at o'dark hundred with water up to my neck!
When you get out you can basically walk into a LEO job as long as your squared away.
Good luck!
Not your every day MP picture;