That thing looks incredibly complicated! They say that you can knit a sock on one of those in 90 minutes. But does that include all that set up time?! I think it's something that if you like that sort of thing and get used to it, that you would be able to use it pretty easily, but it just looks as if the woman in the video is constantly fixing and adjusting everything. And it looks like it doesn't do the 2nd half of the foot-- that there's still a lot of hand knitting to do! I guess there are people who would love one of these, but it's not for me, that's for sure. There is a site that sells restored ones for close to $2000. The eBay ones are from $200 - $1100. You'd better love socks at those prices
. The addi one they show only has the first part of the video up-- be interested in seeing the 2nd part.