I really can't add much to the thorough review by Media Man, I agree wholeheartedly with his assessment.
Being an audio junkie, I judge such things for both the musical qualities and the audio qualities. This OST is excellent in both respects. Very nicely mastered, it provides plenty of audio quality to enjoy with a decent audio system. The skillful use of real and synthetic instruments and samples stands in glaring contrast to most of the junk passed off as a "soundtrack" for games. I seldom buy game soundtracks, I usually just extract the audio from the game files, but this is one of the few I've heard recently that I wanted to have the production mastered versions, and to send some well-deserved shekels to the publisher and artists involved.
I'm not sure if I could choose which of the composers' work I prefer, since I enjoy pretty much every song in the collection. I often play other games with this soundtrack as the backing music - I just never seem to tire of it.
There is a caveat, but one that should not catch you out if you've done your homework: there are songs used in the game that are not original compositions done for the game, and due to licensing, are not in this collection. They can be had on recordings / mp3 downloads of the respective artists. No big deal.
I will again direct you to Media Man's excellent, detailed review for more information.