Colour for me. I think the shadows work well on the closest boxer for BW but not so much on the second. The colour seems to have more impact if you excuse the pun.
it was an Executive Fight Night event. bankers bashing each others' brains out. all for charridy. I was providing the ringside shots plus a photobooth. shot on a 14mm, 85mm (this one), and my 400mm.
I think it is surprisingly successful in B/W especially against that black background. The only sacrifice seems to be the ropes. But it also makes it look as though the boxers have totally different skin colour; this is not as strong in the colour version.
So. I would swing towards the colour..