3D vision seems to come and go

$799 is expensive just to view 3D photos which is my main aim.

I agree, but I bought it anyway.  I got an open box unit from Amazon for $750 which is still too much.  There was one recently on eBay with some extras for $650 that was a good deal by comparison.  But that's gone now.  In any case, I'm pretty hard core about s3D photography, so it was a must have, even though it is far from perfect and way too expensive.

Referring to the web site, it does not tell you how to get the photos or video to the device.

Well s3D video is dead simple, just plug an HDMI cable into your 3D Blu-ray player.  This seems to the primary market that they made this device for.  And gamers I suppose.

Also it does not tell you what type of photos and video the device accepts.

Stills (and videos I guess) can be read from either a USB thumb drive or a micro SD card.  You can use the standard photo gallery program to view SBS with pillar boxing for 16:9 aspect ratio.  Or you can load a third party s3D viewer app that understands MPO files and it will format them automatically to fit.

Maybe other similar devices will come on the market in the near future.

Well there is always the hope that something better and cheaper will come along, and with electronics technology that is almost always the case.  But with digital s3D I've found that it is best to get it while you can.  The best purpose digital 3D cameras, the Panasonic 3D1 and the Fujifilm W3 are no longer made, and both now command a premium price if you can find a new one.  No more s3D TVs being made either, although those tend to be a bit easier to find used at a good price.  But given how specialized this viewer is, I decided to bite.  I think seeing a better one in the near future depends upon how popular VR becomes.