1) Yes, it tastes better.
2) You will be able to make it at a cheaper cost per pound of ingredients but it will take a while to recoup equipment costs.
3) I recommend electric.
Now, all that said, You should absolutely do it!!
I started this with a hand grinder picked up at a hardware store for $20. Now I've got about 2K in equipment. If it were me starting again, I'd get the Kitchen Aid grinding attachment and a 5# stuffer. That is all you need to make it very enjoyable. If you are a hunter, you will save a lot of money over store bought sausage. I can make venison sausage for $1 lb. store bought at $4-5 lb. but once you make your first batch, you won't care whether you're saving money or not, it tastes that much better!!! Plus....It's a lot of fun nd very rewarding.