Thank you Libblo, for your nice insight. I have to applaud your keen eye for detail - don't know how many people routinely pick up on the different-collored highlights. I did feel the fill flash was needed actually - the sun was directly behind him, and I did not want to blow the sky out with extra exposure. I hate relying on the post-processing D-lighting feature, it loses some details (and feels like cheating...). The highlights on the left buttons are not direct sun, but reflections from other brass instruments in the band to his left, the sun was actually behind him as I said. You have a point about the sky, I may be able to crop a bit more out, the impression he is playing against the sky should remain even with less of it in the picture.
Any other input is welcomed heartily.
Cheers.