I thought about the KitchenAid attachment last year but after watching a lot of people struggle with pork, I chose to buy a "real" meat grinder. Most of the troubles I saw or read about are exactly what you are talking about as well as the fact that it can take a long while to process a lot of meat if you want to. The throat on the KA attachment is small so you really have to spend a lot of time prepping your meat for grinding so it doesn't jam. I also noticed a lot of people really had to push to get meat through the throat and into the auger. Sinew and tendons can get wrapped in the auger and will need to be cleaned frequently in order to maintain smooth operation. One way around that is to cut meat into really small pieces and trim it well. But that's a pain in the ass. Another thing with the KA is that the machine can heat up quite a bit and cause the fat to melt, which impacts the final sausage quality. Chilling the meat helps but as you know, it has limitations.
I have no
experience with manual grinders but I can imagine it's a lot of work. I don't blame you for seeking another alternative.
I think it might be worth while to sharpen the blade of you current grinders and see how well that improves things. It certainly could be worth the effort.
Now I'll tell you what I did. I bought this
Meat grinder. Because I knew I'd eventually be raising pigs I wanted to have something that could make the work go really fast and smooth. This grinder is no joke and actually took longer to unpack than it did to grind two hog shoulders worth of meat. It literally eats the meat. I only needed the plunger twice to clear the throat. The auger accumulated a small amount of sinew but not
enough to inhibit the efficiency of the grinder. It's also quieter than the KA and you only need to cut meat into strips 1.5 -2 inches thick. Changing plates is super fast and cleaning it is pretty easy as well. There's not a lot of places for stuff to hide. Of
course there are a million attachments for stuffing, mixing and jerky so it's got more than one function. A little expensive but in my mind, well worth it being that I have six pigs out on the pasture and it's getting towards "that time".
Good luck