When I first rode full suspension I noticed how much better the brakes work, especially the rear. Instead of bouncing around, the wheel follows the bumps and traction is better.
The other thing that stood out right away is the ability to pick any number of lines, or no line at all. Instead of having to pick my way through the rocks and bumps the bike can safely plow through stuff.
And yes, the pro racers are amazing, cross-country greyhounds or downhill juggernauts alike.