Scan times are average for comparable flatbeds, though using the built-in Digital Ice defect removal will lengthen scans by as much as 900 percent. You can also use the dust removal capability that's part of SilverFast, lengthening scan times by only 50 percent or so. Digital Ice is better, but you get what you wait for.
The 4990 won't deliver exhibition-quality results, but it can aid the digital work flow by conveniently converting film to digital data. This lets a photographer quickly examine an image (or series of images in batch mode), tweak it in an image editor, and produce usable output fast. Even a studio with a drum scanner onsite could find such a high-quality flatbed welcome for down-and-dirty turnaround. For the advanced amateur, on the other hand, a desktop film scanner would be more useful overall, unless cost is a key issue.
We compared the 4990's scans to those from a drum scanner and from a Nikon Coolscan 8000ED. Naturally, the drum scanner had the best results, but while the 8000ED was sharper than the 4990, it scored lower on color accuracy. (However, the 8000ED work was done at a lab, so its calibration might have been off.) The 4990's images were softer but well saturated, with a creditable amount of detail in shadow areas. In short, if you don't mind doing Photoshop corrections and limiting your zooms to 100 percent or less, the Perfection 4990 can produce quite satisfactory scans.
Photographers considering the Microtek ScanMaker i900, with its broader dynamic range and sharper film scans, shouldn't overlook the Perfection 4990 Photo, especially if money is tight.