I find that VueScan works very well and has a host of adjustments not available on Polascan not the least of which is OSX compatibility. It also freezes occasionally which is a bit of a bore but by saving the adjustments as a ini file I can restart the program without rebooting of course on OSX and I lose just a minute and continue on. I think the multiple pass feature is excellent as the images when double scanned are more contrasty and sharp. Excellent software with just a tiny flaw.