I decided on the V600, but not without a lot of research and some frustration. Here's what I've found:
Film scanners on the market are divided into three categories:
* One-frame-at-a-time film scanners like those sold by Plustek.
Plustek apparently offers great technical support for its hardware, but the software supplied by SilverFast is going to leave you on your own for most things. All of their under $1k scanners worth considering only scan 35mm film and use a manual feed tray. As others in this thread have noted, you're likely to get your best results for 35mm film from these. They are also small and compact, with a handy carrying case.
As you pay more for these models, you get infrared dust removal for chromogenic films (C-41, E-6 and Kodachrome), and fancier versions of SilverFast. If you want the best image quality, get a copy of SilverFast that offers multiple exposures.
The 120 model scans medium format film at a premium. The 135 model supposedly offers an automatic feed tray, but doesn't include SilverFast and has only gotten negative reviews from what I can find.
* Flatbed scanners like those sold by Epson.
Epson's technical support appears to be universally regarded as terrible, so I recommend avoiding it all costs.
That being said, their scanners and software appear to be well-regarded. The V600 is cheap ($200 at B&H or Amazon new; $145 refurbished through Epson) yet still produces decent image quality, if the customer photos on the web are anything to go by. The V800 series produces better image quality and SilverFast bundles at a significant price hike.
The difference between the V800 and V850 comes with an upgraded version of SilverFast (SE vs SE+), an extra set of film trays, so you can queue up another set while the first scans, and a liquid film tray available upon request for free (a paid accessory for the v800).
The v800 series replaced the v700, now available on the used market. The upgrade added faster warm-up times and anti-Newton ring glass to the film holders, which some have said decreases image quality. Recent Q&A on Amazon suggests the v8xxs may no longer ship with the glassed film holders. I've also seen reports that the medium and large format film holders in the new series were measured incorrectly and don't actually fit those sizes of film.
Special purpose scanners like those sold by Hasselblad, and those that used to be sold by Nikon and Fuji.
Hasselblad scanners produce stunning results, but are out of my price range, at least. The Fuji Frontier scanner AtitG mentions appears to go for several thousand dollars used, and the Nikon Coolscans are well regarded, but also quite pricey. It's also worth considering that you're buying a discontinued product, with spotty support for new OSes.
The things that were most influential in my decision were the customer review photos for the V600 on Amazon and B&H paired with stellar reviews; a Reddit thread comparing image quality between the v600 and v800, and my own experiences scanning film with the OpticFilm 8100. If there's interest, I'll share some scans when it arrives.
---------- Post added 09-18-16 at 10:07 AM ----------
Originally posted by Imerino I actually didn't consider that very thoroughly. I saw that Pentax offers some sort of accessory in Japan, but didn't know that it could be done more cheaply without being exceptionally crafty. I've already ordered the scanner, but I'll return it to B&H and give your suggestion a go if I don't like the flatbed's results. Thanks!