I've done it in all three. The oven or smoker work quicker to get the meat dried out. I like the gorund jerky better, seems to get more of the seasoning into the meat and I use the jerky shooter or I will take drop a handful of meat in between to layers of wax paper and roll it out until I get the right thickness and then cut into strips and place on racks and put in either the oven or smoker for 2-3 hours at 170 degrees.
As far as the seasoning, garlic powder, salt, pepper (either black, white or red pepper flakes) soy sauce, liquid smoke, and what ever else you want to add, Let it sit in the liquid for as long as you want, I usally will not let it sit over 1 day in the fridge.
When I use the smoker, I use either alder, pecan or maple disks.