"Butterballs" and their copies are mostly marketing gimmick, and they cost more that plain turkeys, usually. In my experience, most turkeys arrive with plenty of their own fats still included and do not need extra fat to make them more juicy and moist. As it happens, in our family several people really dislike a lot of fat, so the added stuff in Butterballs is a negative. In fact, in preparing the turkey I normal cut out all the large fat pads still there and leave only the smaller deposits. I roast in one of those large covered roasting pans with a dark blue enamel baked-on surface. The finished bird is quite moist, and the juices collected in the pan have less fat in them this way. That's important because the family likes LOTS of gravy, so I siphon out the juices with a baster and make a pot of gravy, sometimes adding a bit of water so it makes more. The gravy is plenty tasty, and has less fat content than if there were more turnkey fat or butter in the bird to start.
By the way, a comment on the roasting pan. As I said, the one I use is big with a speckled dark blue baked-on enamel finish. It absorbs heat really well, thus speeding up the cooking process, but keeps the moisture in. The result, interestingly, is that I can roast at a wide range of temperatures. 325F will take a long time and cook gently. But If I'm late getting started, I'll turn it up to 400 or 425F and cut the cooking time much shorter, but it still comes out moist because it's closed in. I baste a couple of times during roasting, then take the pan lid off for 15 - 20 minutes at the end to brown the outside.