Hm... is that Edirol Orchestral you used here? It's not a bad library, but its instruments are quite easy to recognize, as they have a very specific tone to them. That's not a bad thing though, but it's always funny to recognize other libraries. That said, here's my review (second time I write this, because Flash Player decided to die on me right before I wanted to click the submit button).
Let's start with the mixing aspect. There are two things I'd like to point out here, both regarding the percussion. The bass drum is a bit too overpowering, in my opinion. It would be good to cut its lower frequencies, so that it fits the overall mix better. The other percussion elements are a bit too 'sharp' sounding, which sadly makes the piece unfit for ambient settings.
The composition itself is also not without its flaws. To be honest, the piece is a bit chaotic, and because there is no clear melody, it is also quite difficult to listen to. The arrangement, however, is the big selling point here. The image you describe (the clouds and all) really comes forward because of the different instruments you used. Good job there!
All in all, it's a decent piece of art. If I were to give you some advice, it would be 1) to spend more time on the mixing aspect of music production, and 2) to invest some more time into studying music theory.
Good luck with your future productions!