I use my wife's 45 year old Kitchen Aid with the add-on attachment on it. It works like a charm on venison, hog, javelina, etc. We were worried about the strain that this old warhorse was taking from it, and when we saw another one at a garage sale for $5, we bought it to put in the garage for reserve. With an extra in reserve, we run the old one hard, and find... it runs like a champ! I'm extremely impressed at the good ol' Kitchen Aid mixer!!!
My wife's parents got inovative about grinding-- they hooked up a decent-sized fan motor to an old cast-iron handcrank mixer that they had removed the handcrank from. They mounted the assembly to a rolling table and put a light switch on it, and I swear, you could grind up a holstein in under an hour with it, if you had it cubed.
The main secret is to cube your meat before grinding, and to every once in awhile clear the grinding plates of any fascia and connective tissue that might have gotten caught on it. This is quick to do, and doesn't need to be done toooo often.
Make sure you've got a sausage stuffer, too!