Biggest negative I saw was how rough it left the field. I also know a farmer who quit putting down n with his because he was getting too much burn. His opinion. He now puts down his nh3 in the fall. Like I said his opinion fact or not, I have no idea.
There are a few downsides but the real problem is there is no upside. What are you trying to improve over regular seedhawk. Row spacing. Thats not a real world problem for prairie crops. Go with regular, save money, less dirt flying, less disturbance and better yields