Thanks Keith, I've read your review now - as usual, well articulated and illustrated. Of course apart from Lightroom it would compete with Nik Silver Efex Pro 2 (which does integrate with Lightroom as a plug-in), also an extraordinarily capable piece of software.
Many people may consider Lightroom integration an important question, because the Lightroom clientele is huge for good reason - won't divert the discussion by going into all the good reasons for using Lightroom, but a salient one in this context is its seamless integration with both Photoshop and Nik Silver Efex Pro 2. Using Lightroom, I find it a largely self-contained highly capable image editing application from Ingestion (Library) to Print, Book or Web, for which I don't need to render about 95% of my images, whether I print in colour or B&W. Anyhow, thanks for bringing this product to our attention. I can see the layers feature may make it a worthwhile addition to the image editing arsenal. Worth some comparative testing relative to the obvious comparators.