I've been using Silver Effex since paying for it a long time ago, 2010. I've been using it in Photoshop as a smart filter as one of the last things I do with an image before printing (sometimes I do some minor modifications above the Silver Effex layer). Sometimes it's better than a Photoshop black and white layer, sometimes not so different. It is easy to ruin an image with overuse of things like "structure" and "soft contrast." My favorite photographic artist, and best Photoshop teacher, Charles Cramer, does not use any of these products, and makes pretty impressive images without Nik (and without luminosity masking either, by the way).
I do not use it in Lightroom at all and only occasionally use Color Effex. In playing with the trial, I've not seen any changes for my use. Aside from the admittedly unscientific comments about speed, has anyone noted any significant improvements in any of the modules?