I used to play bass in my high school jazz band, and we did music like this from time to time.  It takes special skill to mix a horn ensemble, but you pulled it off.  This is very nostalgic for me, and I love it.

It sounds very nice. I prefer not to make changes in mix when the whole track is not ready. But if I'd imagined that vocal is already there, I'd tried to add little bit of ambience (short reverb) on all winds and place it on a second line on the stage (more distance) and make it a little bit smaller.
Waiting for vocals :-)

I am with Spacealf in that the sound staging needs to be better arranged, for me here it was slightly right heavy with little in the middle.  I did a total pan reversal and it ended up left heavy if you understand my furry ways.  As to any reverb I would only use a general shared reverb that would just place everything in it own space within the space.
 
Thanks for sharing.

Thanks for the knowledge, guys! I'm glad you enjoy the track, it was a pleasure to record :)
I definitely agree myself on that I could separate the individual instruments a bit more. I ran with the suggestion to carve out a space in the middle, but I don't think I went WIDE enough, nor central enough. I'll work on that.
Wookie, when you say it's 'right-heavy', you're saying the entire mix is weight towards the right? I (think) the rhythm section and the saxes were all panned right, so I can see why that'd be. I'll try to balance that out to be a bit more central.

Yes, I would bring the Sax in as suggested above at between 25 to 35% on the right and do the same with piano on the left.