I have quick disconnects on my Sportsman 600's rear sway bar, only certain circumstances do I ever use it though. Very unstable, and quite prone to rolling on side hills that load one side of the rear suspension.. I will eventually remove the disconnects, and reinstall the sway bar permanantly.
IRS is better IFS is better, better is better... once the riders catch up with technology.
Independant suspension with the technological advances being made today is better than old school suspension. It's all about keeping the tires in contact with the ground. Acceleration, Cornering, Braking, etc... all depend on contact patch. If one tire on a solid axle set up hits a rock or rut, it affects the way the tire on the other end of the solid axle is hooking up, and usually it's a negative effect. Independant suspension is all about keeping the rubber planted, by allowing each tire to follow the terrain it's encountering, instead of reacting to the input on another tire, a couple of feet away from it.
It's racing technology being passed to the every day user. If the racers can go faster with it, odds are, it makes a better recreational vehicle.. not all the time, but most.
Did you read up on the Tire Balls?? Now that is a great concept, take a look at how many of the top riders in GNCC and other races use them.