Good stuff, although there is one thing I'd definitely suggest:
A little more work on defining foreground vs background would not hurt. That is to say, the characters themselves are fine and the background looks great. On the other hand, the area (including the railing) that everyone is standing on seems like it can't make its mind up between folding like a cheap suit and melding into the background or popping out a bit more to be a fair portion of the viewer's focus.
Either way, that's my two pesos.
Keep at it,
thanks for the feedback! I added some depth of field blurs in the final composite to try and push foreground vs background more. Check it out when you get the chance :)