The first 55 seconds of this track make me feel horribly uneasy. It's a really unpleasant part to listen to but it fits nicely to the film. I bet those Gondorian soldiers were feeling a bit uneasy, too, while keeping watch in Osgiliath.
At 1:15 begins a theme that is titled as "Minas Tirith Song" in the sheet music. I love the majestic part from 1:38 to "Mithrandir's Song" (~2:00) and Ben Del Maestro's solo. My favourite has to be Gondor's theme, though. It gives me shivers when at 2:53 the d minor chord (the sheet music has no f in that chord so there are just d and a, but anyway...) turns into Bb major. I wish they had played that whole theme louder so I didn't have to turn the volume up every time I'm watching that part of the movie (though I should probably blame those people who mixed and mastered the score).
I think the brass are an excellent choice for Gondor. As a country which has fought for ages against Mordor, it's theme should have enough feeling of an ancient and noble culture and the bold wind instruments do that perfectly.