If you can't hold the film flat, autofocus isn't much help. I bought a betterscanning holder for my Epson 4990 adjusted to the optimum height, started fluid scanning on it and have been very pleased with the results so far. Visible grain is reduced in color negative and color seems to be more defined on the slide film. Its not going to change the optical resolution, but it does improve the scans.

Fluid mount versus Epson holder example

Fluid Mount versus dry mount on Betterscanning holder

Not every film is showing this much difference, but Astia seems to benefit greatly from the fluid mount.

Coupled with the fact that Microtek isn't exactly earning a good customer service reputation, I think the Epson V700 or V750 with a betterscanning holder is a more appealing option today. Epson has been updating the drivers to keep up with OS requirements too. They've certainly earned a bad rep there too, but they're keep the V series scanners up to date.