Silver Efex is a regular part of my workflow for large B&W prints, but sometimes the settings that work for one part of an image can give artefacts in other areas (even using control points to vary adjustments)
However there's nothing that says you can't use it multiple times - I've written up some notes on this that may be of interest?
http://www.northlight-images.co.uk/article_pages/photo-tips/sfx-halo.htmlI've also used it to selectively enhance B&W images, by changing them to RGB mode, running the filter and then using it as a very selective contrast alteration tool, by 'painting in' adjustments. Like most of these tools there are lots of ways of using them beyond the 'click here to make a B&W picture' mode ;-)
