Although both use the same principle, they look like night and day apart. The first is very cool. I like how there is little waste of material. With the second, having to initially pour out so much to get the thing started means that lots will be wasted. I imagine you have to babysit the first one by always squirting more on the roller though. For the second, having to waste more canvas since you need quite a few inches to get it started is a bit worrisome, as is the fact that pulling it is highly irregular, and if you stop mid way, I imagine this might cause a line or streak in the coating.
$2500 seems a bit steep for just a bunch of metal rods with a motor, but if you're coating 100 canvases a month, hence 1200 a year, its only $2 per canvas for the first year if you look at it like this. If you're really spraying this many canvases a month, I would go for it!