When set up properly both the UCD and the Fusion fly equal. The Fusion is better in KE and and Harrier maneuvers. The UCD is better at flat spins and rolling circles and is easier to hover. Waterfalls are close but I'd give the nod to the UCD. You can mount the tank on the CG on the UCD but not on the Fusion. The Fusion is clear more sturdy than the UCD and will take a tougher landing.

Thanks
Barry