I've been using a borrowed 4490 while photographing in Portugal this past month, and I've been very impressed! This thing is sharp, quick, and the MF film holder is
far better than the tweaky holder on my V750 at home. It has a smaller "gate" (film window), which may indeed keep film flatter than in other scanners. I now understand why other users of the 4490 have not seen the need to "move up" to the V500/700/750.
The only downside I've found is that because the MF holder's gate is so small -- 6x12cm -- it is more of a process to use it as a "contact printer." On my V750, I can quickly scan an entire strip, and the included software will (usually) split it into individual images for each frame.
It's not a problem for single images, and you'll get a couple more frames with 6x6 or 6x45. Since I'm shooting 6x7, scanning up a roll of ten exposures takes a bit of time.
You can see some at the links below, all @ 600dpi, post-processed in Lightroom, and downsized slightly for Flickr:
Or more at
my Flickr page (the color images are from my iPhone; the B&W images are from my RB67).