What is the vehicle/axle? If you have the square bolts pointing down, that's definitely worth changing. But for round U-bolts pointing up, there's almost no ground clearance advantage to eliminating U-bolts. There are potential drawbacks to the UBE because the bolts are MUCH shorter, therefore less stretch/durable clamping force. Also, they rely on good welds on the spring pads or eventually spring wrap and axle torque will rip the mounts off.
Or do you have some interference on top of the axle, like weird bumpstops?