yeah ok, I'm pretty sure it was the marines my dad looked into... so it is true. I'd be careful about signing anything with them.
It's true that all Marine officers, whether they will eventually fly jets, command a tank battalion, or become lawyers, must complete the same 10-12 weeks at Officer Candidates School (OCS) and 6 months at The Basic School (TBS). Just as every enlisted Marine is first and foremost trained as a rifleman, every Marine Officer is first and foremost trained as a rifle platoon commander.
But I have a slightly different perspective than most on this board as to whether you should consider Marine Corps JAG. I completed the first half of Marine Corps OCS before an over-training injury prevented me from attending the second half on schedule. I ended up going to work as an engineer with the intent of eventually getting back in shape and returning to finish up OCS. However, because I got caught up in other business activities, I never did return.
Although I've done well financially, not returning to OCS is a decision I sometimes regret, because my experience as a Marine officer candidate was incredibly satisfying. If you like a mental and physical challenge, and the opportunity to hone your leadership and problem-solving skills under stress, there's no other way to go in my opinion. Also, having been an enlisted Marine for 8 years prior, I've had the experience of working with people I would actually entrust my life to. That feels good to me, and it's something I can't say for any civilian job I've had.
When I was there (1995), OCS had about a 33% attrition rate. One of our sister platoons lost around 50%. But for me that was part of the satisfaction -- not knowing if I was still going to be there 2 days later. Most people run from those kinds of odds. You have to live in the moment, focusing on each task like it was your last opportunity to prove you have what it takes to be a Marine Officer, often with very little sleep and very sore muscles. It's not for everybody, but that short experience prepared me well for many of the challenges I would face later in life, like starting up successful business ventures and going to law school. As you can imagine, most of the things my classmates whine about just make me laugh (inside, of course).
Most advice you get from law students is tunnel-visioned. It's generally based on the premise that military service is just a distraction from your development as a lawyer. In reality, the training you will get as a Marine Officer will make you a lot tougher and more disciplined mentally, physically and emotionally than most of your peers. Lawyers frequently deal with unforeseen stresses on a daily basis, and this is where that toughness and discipline pay off (I've seen it first hand, both in school and in business). If you're a great lawyer when you rejoin the civilian world, other lawyers and law firms will take notice, and they'll bring you in as an associate or a partner laterally, regardless of where you spent your first 4 years as a lawyer.
Best of luck.