Matt have you seen comparison pics of a 4 inch Superlift using brackets and the 4 inch BDS using both upper and lower adjustable control arms? The proof is in the pudding. As far as compression (stuffing the rear tire into the wheel well) the Superlift kit using the brackets pushes the rear tires into the door as the BDS using adjustable uppers and lowers with no brackets centers the tire at full compression in the wheel well. Can you guess what happens when it comes to flexing out the rear end? Again pictures don't lie.

I'm not sure where you get there are no performance benefits to the adjustable over brackets. I guess you would rather have your tires getting pushed into your doors at compression and flex due to the changed pivot point by using brackets. Still not sure what the negatives are because normal driving the axle will be centered perfectly side to side and front to rear and it's not going anywhere. Off road it still stays centered like on road which doesn't happen with the brackets supplied by Superlift.