I have the LEM #5 electric grinder. I'm really happy with it. The biggest disadvantage is that you have to cut your meat/fat into fairly small pieces, say around 1" in size, to fit through the feeding tube into the auger. But the grinder has a great bite, I have no trouble with smear or clogging as long as I trim off the really stretchy sinew and keep my meat/fat cold. I can even grind chicken skin with no problem.
I usually make 5 lb batches of sausage. It only takes a few minutes to run the 5 lbs through the #5 grinder. I also usually do double grind. The second time through the grinder is more tedious because the ground meat doesn't fall through the feeding tube, you have to push it with the stomper. Because the feeding tube is narrow, there is a lot of suction when you pull the stomper back and so it is a little tougher to feed the ground meat through. However, it still only takes maybe 5 minutes to run the 5 lbs through the second time.
Hope you find this helpful. I'm sure you will be really happy with either the #5 or the #8. And the customer service at LEM is fantastic.