I picked up a CV64/3D + scandoubler earlier this year, and agree the image quality is great. Games and demos look fantastic through the scandoubler ("Revelations" demo is STUNNING on a Trinitron), black text on a white background is also surprisingly sharp. (Actually, in some side-by-side comparisons the other day, it held its own against my new Indivision.) It does not deinterlace, though.
Can't check for 24-bit output, as I'm running mine in an A2K. ;-)