I have recently purchased one of these scanners, expecting more than what I got......just talking about the scans.
My take is my unit is out of focus. Doing a usaf1951 target scan I calculate about 2500dpi. But when I go up and down the resolution(s), I can see a difference between the scans @2500 and @5000, so there must be more. I can see grain focused on the edges, but get into a blur approaching the centre of the frame (neg is flat). This makes me think it's focus. This is consistent with silverfast (puke), cyberviewx and vuescan. Vuescan has a setting for manual focus that doesn't seem to do anything.