The Seafoths have recently been running a basic unarmed combat course for anyone interested. Our Ops WO is unarmed combat instructor qualified, and has been kind enough to run it and share his skills. The skills themselves are very little like any martial art I've seen. As was mentioned, it's meant to be done with webbing/tac vest, body armour and a helmet on, so the moves are a lot more restricted. When you have about 40 pounds of gear on your torso, kicking someone above the waist is pretty useless, and you're more likely to land flat on your arse. There are no "points" and very little in terms of rules. In most martial arts, certain moves, hits and parts of the body are off limits, but this doesn't really apply to the military; as you're likely about to be killed and nobody's going to deduct a point from you if you kick a guy in the groin.
As for regular martial arts, they will certainly teach you strength, agility and flexibility, and will prepare you for what you will learn, but will not be the same style. It's a great fitness program, and will get you in shape, but be prepared to learn something different in the army.