I've done it with and without doing my own brine with the same brand of Turkey before. There's a difference as you can add more seasoning to the brine, and other flavors. Plus the Turkey does not taste over brined (I've done that before as well by accident)
Yes the fat does roll off, but that's basically what basting is already. I have also done the Turkey with and without bacon, and there's a difference as well. I've also done it with and without tinfoil on the breast as well because the breast does cook differently than the rest of the Turkey. The key thing is that when you're cooking the Turkey if its brined it will pull juices and flavor from the surface of the Turkey inward. This is mainly done because of the salty brine. The bacon is in lieu of the tinfoil because I feel like it shields and insulates the breast better, and it is actually easier to lay bacon than tinfoil.
I did buy a couple birds so ... and I have gotten better and brining. I can try to do it with or without bacon.