I have the attachment that goes onto the KitchenAid grinder attachment. It's so simple and easy to use, it boggles my mind why it wasn't included with the grinder in the first place.
I've yet to make sausages with it though. The grinder was a Christmas gift from my sister and the attachment for sausage was bought with a gift card. (Also from my sister. :D )
I did use it in school a few times and it was flawless. All it was, was a screw on attachment that replaces the meat grinders cutting screens with a tapered 5 inch tube or so that the casings get gathered on. When the meat is forced through the tube, the casings catch it. It is VERY easy to control the speed so sectioning off link size won't be a problem after two or three tries.
I have such fond memories of making bratwurst right now. Poaching them in beer, finishing them on the grill, splitting open a few 10 minute old baguettes, stirring the mustard.....
OK, my stomach gust growled so loud, my beagle Riley just looked at me.