I'll weigh-in.
I've tried several recipes and never been quite happy. Recently I used a Lem seasoning package to make some mild and some hot Italian sausage.
I have no complaints as to taste with either.
Plus you can mix up small batches, 5-10 lbs at a time.
Not exactly a "recipe" but at the same time, I can mix the meat as I wish as far as fat ratios or adding venison and I know what's going in there. The Lem seasoning packet just simplifies the process.
Who knows what is ground up in the prepackaged sausages.