It's pretty good. The music is fairly interesting (I wouldn't say it's that unique, but it is interesting enough to not be generic), and the instrumentation and overall sound is very believable/professional.
My only complaints:
1.) Like Roph said, there are a few points where it really seems to drop out. As if the backbone of the track suddenly dies out, or gets immediately quieter. It's very jarring, and the momentum of the piece suffers because of it. (And momentum is important in a battle theme.)
2.) I don't like how you treat certain instruments. You introduce them for mere seconds, and then they disappear again. The flute/piccolo comes in (0:34) and leaves just as quickly. After that, a brass thing comes in (0:47), but only for a second, and then it's gone. I feel that you're selling these parts short. You bothered to give them a part in the piece, so give them a bit more development, a little more time to express and idea before you move on to the next "solo" instrument.
Same goes for the harp. Harp glissandos are cool, but come on, use the instrument for a bit more than just that.
(Same thing goes for the marimba at 0:28. You use it a few other times, but just as an accent. If you're going to introduce such a unique instrument, be prepared to give it a larger contribution to the piece as a whole.) I was going to say that, but then I heard it being used later in the piece. It was hard to notice. Maybe you should make it a bit louder, so it stands out more.
3.) The first brass solo at 0:12, the sample needs more attack. The notes swell, and because of that you kind of lose sight where the downbeat is, and when the string come back in it feels like they're too early, even though they aren't. Just tweak the sample's settings a bit so the brass notes are played a bit more immediately.
edit: Sorry, I'm a tough critic sometimes. :p