Hi Chris,
I used this scanner since it first hit the market; used the Epson Expression 1600 before that. The only reason I upgraded to the 1680 is because the prior version really couldn't do true 1600 ppi scans. Epson's marketing material stated that it was a 1600 ppi scanner, but I as well as others of greater expertise than myself knew that it was really on 800 based on testing. The 1680, on the other hand, really does 1600 ppi; I scan for optical resolution only.
If you really want to see this scanner shine, buy SilverFast Ai Studio 8, a calibration target, and a betterscanning.com film holder. I also wet mount my LF film directly on to the glass with Kami fluid with a mylar cover sheet. If you scan B&W film, IMO you can't do better than using SilverFast to obtain a raw scan, then using ColorPerfect (c-f-systems.com) to convert to a normal looking image.
Vuescan also works well with this scanner, but doesn't have the dual-focus option that both Silverfast and the Epson software have. Therefore, though I do own Vuescan I don't use it with this scanner.