6 is the best for me too, although I quite like the 'copper'.
Perhaps you should look at your numbering policy?
In the first four shots the light is very harsh and not condusive to good portraits (leads to squinty or blocked out (with shadows) eyes and mega contrast) and would probably have been helped by a little burst of fill-in flash, and 5, 7-9 you have suffered a bit by exposing more for the overall image rather than the for the subject (if a portrait then the facial skin tones should really be correctly exposed, as opposed to a record shot, to which these are more akin), whilst I realise that people in-situ pictures are taken as are, there is no real reason why numbers 8 & 9 (my numbering not yours
) should not be correctly exposed for the facial tones (I realise that this will blow the background, but there is nothing in either of them that is of importance, and you could if you wanted subdue the backgound a bit in PP).
Taking a good portrait of someone inside a vehicle is actually quite difficult and usually requires more than just the photographer and the model as it usually involves bouncing some light into the vehicle to balance up the contrast between inside and out.
So 6 gets it for me as the exposure is better, he is not squinting into the sun with panda eyes and the exposure of the vehicle is good (colour maybe could do with warming slightly).
Sorry to be seem so negative Matt, but you did ask for some C&Cs.
Oh and I won't say anything about the last