I use a Nikon Coolscan V ED for my 35mm scans, but recently picked up a V500 for medium format. I never used the stock, flimsy, floppy, 2-frame-only film holders. I had already ordered the variable height holders from betterscanning.com, and I love them. I also use VueScan exclusively on both 35mm & 120. Great results. I find I always scan at 3200dpi rather than the available 6400 though. I haven't needed the 180mb(!) files from 6400dpi. The 50mb files from 3200dpi suffice! 😉
Oh, and I looked at the V750 before purchasing. As far as I can tell, the V750 would be mandatory if I wanted 4x5 or 8x10 scans (shudder.... haven't bitten that yet.... but...) with its second lens. But the V500 is better than okay for 6x6 (with the aftermarket holders) and I much much much prefer the LED backlight instead of fluorescent, for ease of use, immediate startup, evenness of lighting, and ecological friendliness.