Originally Posted by rparmar 
The second one is over-exposed relative to the first, making the comparison more difficult.
I would say in general you'd want grey-scale though. Any tinting could be added to taste in PP.
Interesting you say that, because the only difference (in post processing) between the two copies I posted is I flipped the "Treatment" switch in LR2 from Color to Grayscale on the 1st one.