As a grad from the Citadel I felt obligated to jump in here and defend my school from those evil Aggies. I thought I could give you a quick comparison between the schools from my time at the Citadel and talking to the numerous Aggies in the military.
Texas A&M- A big school in every sense, it has 45,000 students. Only 2000 of them are in the Corps if that is what you are looking at though. That means all the good and bad that comes with a big school. World class professors who happen to teach a class of 400 at a time, that type of thing. The Corps itself is not a bad deal. There wear uniforms similar to WWII US Army. They have this big thing about boots.....Anyways, the Corps does not seem to be as strict as the Citadel's, and that is not necessarily a bad thing. Talking to the alumni that I knew, you had many chances to let your hair down (if you had any) and join in on the fun of the normal college experience. If you dropped out of the Corps you can still graduate from A&M. From my personal experience, the guys and gals who have gone through the Corps enjoyed it.
The Citadel- My old school. It has about the same size Corps but that is it, no other students. You live only a mile away from College of Charleston which has approx 10,000 students. About 60-70% are female, but discount about half because that is how many hate cadets. Charleston is one of the nicest cities I have ever been to, and I have been all over the world. As for school life, you are in a military enviroment for 24 hours a day during the week and a good part of your weekend. It is pretty strict your freshman year and gradually gets better as the years go on. No TV until you are a senior. It was a senior privilege to go out during the week (or if you had good grades). While some of the students will never win a scholastic prize, much less know what one is, the academics are pretty tough. The average GPA is pretty low compared to other schools (no grade inflation). The ROTC unit was really good. It was a very small unit compared to the USAF and USA units. We also graduated more Marines than Navy so I had only 15 in my class become Ensigns. The alumni are fewer than A&M but the fierce loyalty is still there. Other than that, I loved it there and would do it all over again.
So, it boils down to what kind of school you want. I needed one that would give me a good swift kick in the a@% and few distractions, which I got in spades. If you want to spend the next 4 or 5 years in a flat brown place where all they want to do is brag about how they could still secede from the US, go to A&M. Seriously, I hope this gives you a little more information on making your choice. Best of luck.