I can help you with that.
First, Ranger school isn't for the weak. I've seen some PT beasts come back from ranger school.
11B's when they aren't overseas are training. drills, drills, drills. You will be able to do drills with your eyes closed.
MPs... not a bad job, per sé, but there is a downside: you don't have the luxury of working 9-5 and getting weekends off. MP is a job that has to be staffed 24/7, even on Christmas. Even on Thnxgiving, even on four day holiday weekends. I wouldn't recommend MP unless you're cool with a schedule like what I just mentioned.
My advice? Go Air Force. 85% of my army colleagues are miserable, including myself. Air force has better living conditions, more relaxed grooming standards, the girls are prettier, the guys are smarter, and air force bases are always neat and the grass is green and so forth.
I live on Fort Bragg... bragg looks like crap (until you go into the officer housing complexes)... the grass is half dirt, half dead grass. The trees are all pine trees. Go onto Pope Air Force Base and it looks like a freaking golf course, no lie. Plus rank is more relaxed in the Air Force.