I bought Xenogears OST knowing exactly what to expect, having played the game. While the game stunned me with its complexity, the musical score stunned me even more. Yasunori Mitsuda created a masterpiece in Xenogears.
I have heard people recommending this soundtrack on the basis of "if they liked Chrono Trigger", and I must say that is a horrible comparison. Yes, some of the compositions are similar; for example, the beginning of "Shebat: The Wind is Calling" is reminiscent of the Enhasa theme from CT (not to mention they are both the themes to floating countries). However, the overall feeling to each soundtrack is vastly different. Chrono Trigger is a very light-hearted game, Xenogears is not. Heavy in religious themes, this is reflected in the soundtrack itself, with beautiful choral as well as organ pieces scattered throughout the two discs.
Altogether, the arrangement of the CD is excellent as well. Lighter musics (town and character themes) are mostly centered in the first CD, which overall has a soothing effect. For example, "Leftovers of the Dreams of the Strong" is beautifully done with its marching, upbeat and heroic theme, which along with the similar but more wistful "Bonds of Sea and Fire" reflects the character of the prince, Bart Fatima. Most of the town themes are very bouncy, with lots of upbeat drumming and nice voice samples woven into the songs that create the atmosphere of a busy marketplace, or a sea ship.
The second CD focuses more on the darker aspects of the game. "June Mermaid" is simply beautiful, and it accurately reflects Emerada's wistful character. "The One who was Torn Apart" and "Omen" are eerie and portray the stunning revelations that unfold throughout the course of the game. My favorite track, "One who Bares Fangs at God", is one the strangest and the most beautiful boss themes I have ever heard. The ending song, "Small Two of Pieces", is a beautiful touch and is wonderfully sung, while the other song that can really be termed "vocal", "Stars of Tears", is a nice bonus.
Even for those who have not played the game Xenogears (and therefore lack the emotional attachment), I still strongly recommend Xenogears Original Soundtrack.