The other ones that are comparable to the Noran in price & quality are the
Insight from Meridian Instruments and the DVC-250 from Biorad.  you should
probably include them both in your evaluation.
 
With most of these units the acquisition time is more dependent on the way
you acquire the image.  The Biorad and Meridian have a simple optical port
that you can attach a video or digital camera to, which means you can go
at video rate you need to, or use a slow-scanning digital camera to
acquire higher resolution images than a video camera will provide.
 
The Nikon and Noran devices include the imager as part of the unit, and
both go at video resolution & video rate.  There are advantages &
disadvantages to both.
 
Happy hunting.
 
Jon Blackburn
Fryer Company
Chicago, Illinois