That degelman looks like a beast. I'm not familiar how it compares but know the TurboMax seems to focus on the straight vs curved coulters to minimize soil inversion.
That said, I'm looking at a pricey 12'. I'm tempted to go 15' since I have 168hp, but am advised that I should go conservative since I have some slight hills. Yet I'd think the 168 would have no problem.
EDIT: I found this info on comparing the Great Plains TM to the Degelman PT:
Key Differences:
Aggressiveness: The Turbo-Max provides adjustable aggressiveness with its variable gang angles, allowing for flexibility between light and moderate soil disturbance. In contrast, the Pro-Till is inherently more aggressive due to its concave disc design and heavier build, making it suitable for more intensive tillage operations.
Speed and Efficiency: The Pro-Till is designed for high-speed operation, enabling rapid coverage of large areas, which can be advantageous for time-sensitive fieldwork. The Turbo-Max, while capable, may not match the Pro-Till's speed in certain conditions.
Soil Disturbance: For minimal soil disturbance and maintaining surface residue, the Turbo-Max is preferable. If deeper soil mixing and residue incorporation are desired, the Pro-Till would be more appropriate.