Most of my photos end up in B&W, but I always work them up in color first, in LightRoom. When I know that I'm going to convert to B&W, I sometimes give the saturation a boost before converting, just to increase the separation between colors. Then I can play with the sliders in LR to get just the shade of gray I want for each color.
I have Silver Efex Pro, and I have used it some, but I prefer to do my conversions in LR. I only pop over to PS for spotting, cloning, or context-aware stuff, and that's all before converting to B&W. I generally make a snapshot of the best color version before converting, then make a copy, convert the copy, and make another snapshot of the best B&W.
Works for me, but YMMV.