You get some sharpness out pure bw sensor, but the drawbacks are that you need to start bringing colored filters like you need in film days. In that way bayer filter has an advantage because it allows you to get exactly the same effect in post production on raw file just because it allows further color manipulation.
Knowing that, things aren't as simple as they looked. There are people that exclusively shoot digital bw, that do prefer bayer filters, because they give you more in post. BW sensors, are not different sensors, they're the same tech, just configured differently. You can in fact turn any bayer sensor into bw sensor via some advanced modifications.
Looking for them specifically your choices are small. For purely bw sensors, you've Leica M Monchrome, even more expensive dbacks, and conversions that you can buy from maxmax.com
. Now there are some interesting alternatives. Sigma's Foveon sensor is inherently different than bayer, images you get out of them preform remarkably similar to pure bw sensors. And you've also pixel shift tech, that give you full color readout of every recorded pixel. So any cam allowing that will give you same results as well, albeit you are restricted to stationary objects and tripod use with pixel shift. >>3523355>Also you would need expensive Apocromatic lenses to get the most out of your monochrome sensor.
That's complete nonsense. Apocromatic lenses have absolutely nothing to do with bw color.