Silverfast is absolutely top-notch. I tried both (you can download a trial version to test after you get you scanner). However, as already pointed out, it is a lot more expensive. Vuescan is very good as well. The Silverfast interface is, from my point of view, a little more complicated than it should be. That may be a result of the cultural differences between Germany (the Silverfast country of origin) and the US. I think that you need to be a little more technically minded to take full advantage of Silverfast. That said, if you are technically savvy or, patient, it is not an impossible interface to master. Both softwares will do a credible job but Silverfast is a little better with truly problem B&W negatives and, color negs (IMO).
If I were you, I'd make my decision about a scanner and then try both Silverfast and Vuescan. Did anyone mention the new flatbed from Microtek? It's gotten great reviews for its' film scanning capabilities. Also, Silverfast comes packaged with this scanner. Hope this helps.
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