Had a pair of 2.4 RQ's which weighed close to the claimed weight, but a buddy needed tires so I gave them to him and ordered a pair of UST's. They weighed 100 / 150g over spec meaning they where really in the range of DH tires. Decided not to mount them and get the regular ones, they where about 150g over spec too.
Nice tires, roll well and grip well. They do have a tendency to roll under with very low pressures, but that's probably due to the huge volume. Now I'm running Schwalbe's (Big Betties). The new Trailstar compound is great, rolls almost as well, better traction, lighter and manages low air pressures better.
I've understood the 2.2 RQ is quite different to the 2.4. It's still massive, but the side walls are thinner resulting in maybe more of an xc tire? A lot of people say they have had sealant seeping through the sidewalls on those tires, while the 2.4's sidewalls always felt pretty thick.
You better check how much clearance your bike has on the rear, I could see a lot of bikes having problems with the 2.4's on the rear.