I have an opticbook 3600. I like it a lot. However, it does have a problem with books with very narrow gutters. I have been reading about camera based scanners at http://www.diybookscanner.org/forum/
, and am planning on building a 2 camera scanner based on some of the ideas there.
I see two issues with the Hovercam. First, it's only 1200x1600 pixels, which, depending on the size of the book, may be on the order of 100 DPI, which is problematic for most OCR programs. 300 DPI or better is preferred. Second, if you're scanning from a book, the flatter the paper, the better. With a scanner like the Opticbook 3600, the book only needs to open to about 90 degrees, so the page can be almost completely flat. If you have to open the book to 180 degrees for the Hovercam, there's going to be a lot of curvature on the page, which makes it harder to OCR, and is not faithful to the original image for an illustration.