my grandfather gave one to my dad. he has since bought three more (of various brands), one of which he sold to my sister. he also has a "viewer" similar to the one in the picture, and even better, has a projector. the projector uses polarizing to make each eye only see the correct picture. it results in a beautiful, colorful 3d image, so unlike the crappy red-green type that they still try to use today.

of course the down-side is that he has to get the slide film specially processed so they're not cut to standard size (they use 35mm file, but the pictures are narrower), then he has to hand cut and mount them individually. he doesn't mind one bit, though! =)