If you have heard glowing reviews at betterphoto about the Epson 4990 for film scanning, I predict you will hear the same about the V700 and V750. Epson says the 750 has a better coated lens and a fluid-type film holder, and a more comprehensive software package.
Scanner interface is intuitive and simple. Scans are consistently very close to dedicated film scanner quality.
Having used several film scanners, I have learned not to pull what's left of my hair out expecting perfect scans from any scanner. I set the scanner to output a high resolution, high bit file that I can tweak in the high bit mode in Photoshop (or Elements 4 or 5), then take it down to 8-bit to save file space.
I scan in the Professional Mode, using the User Guide. Resolution should be at least 2400 for 35mm and at least 1600 for medium format film. Other reviewers have noted that the 6400 max res is a bit optimistic, 4800 being a practical maximum (See the photo-i review). Set the bit depth at high bit, and, for medium format, set the Configuration to the size film you are scanning. Use the generic Preview Mode, NOT the Thumbnail Mode (Thumbnail's auto cropping is sometimes off the mark). Draw a marquee around each of your images, even if you need to Zoom to draw it more accurately. At this stage you can do tonal corrections using the histogram and curve functions, or just the auto exposure button. Push SCAN and all marquees with a dotted line around it will be scanned while you have a quick cup of coffee.
Save sizing hassles by Outputting to original size. This means you will get an image in Photoshop the same size as the original neg, at the high res at which you scanned. Do your image sizing in Image/Image Size.
Additional instructions can be found at www.betterscanning.com by digging into the V700 pages.
This scanner is a natural for folks like me who have been shooting film for 40 years or more. You will get decent results scanning batches of negs or slides with a minimum of bother. Plus you get a superb flatbed for your home office.