I would tend to agree that Silverfast deserves a Lifetime Dog's Breakfast Award for UI Engineering, but the software does work very well once you get on top of it. I would say that it is easier to understand than VueScan, which despite being a sterling effort, does expose the fact that it is a one-person project. Personally I always get the feeling that it isn't entirely clear what's going on with VueScan. Both, in any case, could seriously benefit from a long weekend on Usability Island.
It must be a pretty hard task keeping a film scanning software company above water these days, so I tend to cut them some slack. Lasersoft do tend to try all sorts of tricks to extract money from their dwindling customer base, but I can't really blame them. Sometimes, just sometimes, they still come up with good stuff, like the recent multi-exposure upgrade.