I'm a bit late to this thread as I've been in the field shooting for a couple of weeks.
This will depend on what you are shooting. For example, if you are out west in a hazy national park (I was just in Sequoia and Kings Canyon NP), if you shoot in color you capture the haze. If you shoot in B&W and use filters from yellow to orange to red (depending on what you are trying to accomplish) you can attenuate the haze to a fair degree.
Cleaning up the haze is something that you have to do at image capture. You can't easily clean up the haze from a color image unless you basically completely drop the blue channel, and most of the green channel. Sadly, the red channel seems to be where most of the noise lives.
So, for certain subjects shooting in color and converting to B&W works just fine. For other subjects, shooting in B&W will give better results. That said, when I do this I use color negative film, never trannies. The reason is that even trannies aren't WYSIWYG and require some color correction unless you are shooting in the studio with (tightly) controlled lighting. And if you are going to do some color correction anyway, why not get the much extended dynamic range of a negative film? I gave up trannies long ago....