Very nicely done! You've created quite a neat groove there! Epic, flowing, yet chill and kinda suave. Congrats! I have one or two things you might think about when producing this sort of piece. I thoroughly enjoyed the composition aspect though, so I won't say anything about how it is written. :)
First, I would watch the sound quality of your individual tracks. The strings are high in mid-range frequency, and this cuts through in a way you might not have intended. This can be mended with a little bit of eq, and doubling the strings with either more strings samples or something else to help balance you out.
Second, the texture is quite involved and awesome, and everything ends up piling up in the middle, making it hard to hear all of your elements at one time. I would suggest using panning and reverb to "move" your sections around sonically. I won't go into too much detail, but you can arrange your instruments like an orchestra or live ensemble; pan the violins to the left, the cellos to the right, add more reverb to the horns than the other instruments to move them to the back. If you want to get more in-depth, draw out an aerial view of a concert hall and draw your sections in. Then move the tracks accordingly.
Just a mixing tip or two. Take them how you want. I love this piece, and would not have written anything if I didn't think it was nearly perfect to start with. I give you mad props.