Part of what UAD did right was model the saturation... (Waves has hardly any comparatively.) The difference is pretty audible if you just listen to a sine wave, but it’s especially audible on the 560.
Both have rich harmonics, but the 560 has crazy harmonics.
Attached some screenshots for fun…
Waves 550.pngWaves 560.pngUAD 550.pngUAD 560.png