I too liked Convert to B&W but apparently its time is past. Nik SilverEfex Pro is the way to go these days. Not as inexpensive, but very versatile and feature-rich.
That one is unbearably sluggish on my current machine (which is, no question about it, older and slower than the modern stuff). But what concerns me about that app is the TINY size of some of the UI features -- can't recall exactly which ones at the moment. The resolution on the monitor I'm now using is not all that high. When I switch to a higher resolution, much larger LCD (which will accompany the next machine update), UI elements in any apps that are small on the aging CRT are going to be even smaller yet on the LCD. The smallest SilverEfex UI elements will become possibly near-invisible. Some of that program's text labels were so hard to read against the black background that I couldn't even make out what they said. Those guys must not have consulted a graphic designer, or if they did it was someone who didn't have a lot of experience. In print you NEVER produce thin white reverse type against a black background, because it's going to fill in with some print runs, making the type all but unreadable. There's of course no "ink" on the screen, but the same problem with readability exists with reverse type, which should at least be boldface. Not in that program, it isn't (last I looked, anyway).
So, after reading about the "improved UI" in their advertising blurbs, I was somewhat less than agreeable to the idea that it had been improved. I'll give the demo another look on the new machine. I'll try to be fair about it, but unless the app in question is simply peerless I won't pay that kind of price for an ill-designed UI. Just because someone can
do a less-than-expert imitation of the Lightroom UI, doesn't mean they should