The million dollar question is whether the Nikon 9000 is worth 10 times the price of the Epson 4490. Here's a comparison. You can judge for yourself. I think it is worth the order of magnitude price delta. This is actual pixels from two scans. The full frame shot is the other one for today. The Epson is a flat bed scanner while the Nikon is a dedicated film scanner. As a flat bed the Epson does a great job on photos. I will use that one for its intended purpose.
Now on the other hand, if you want to scan slides and negatives with no intent other than just getting decent images from film or slides, the Epson is fine for that. I just decided that I wanted the best I could afford. Loosely translated that means the best that I could afford to put up with the static from the female member of the household. As a matter of fact when Ginny saw the test scans I had done outside on a Nikon 5000, she agreed that the upgrade was worth it. She is the photographic color and sharpness quality control person here. She has a good eye for it.