I use Silverfast AI Studio and Silverfast HDR extensively for scanning and processing negatives as well as some slides, and for that it works very well despite some interface idiosyncrasies (they don't always follow the Mac interface paradigm). It is certainly a more capable product than the software provided by the scanner manufacturer, and I would recommend its evaluation by anyone serious about scanning.

Although previous version 6 updates have been free, Lasersoft has chosen to charge money for this one (In fact, as of this writing their website still says that all updates to version 6 are free). The cost stated here on Versiontracker is $59, but their website quotes the update price as $70 when I enter my information. Attempting to evaluate the update before purchasing it is problematic at best. Installing the 6.5 demo overwrites the current install which means any scanning work must stop until the evaluation is complete and either a purchase is made or the previous version reinstalled. There is also the question of updating Silverfast HDR for which they have not yet offered any upgrade price. A substantial cost to update both of products would not be worth the few new features in my opinion, and I will hold off if this turns out to be the case.