The Generals are Light Truck / LT rated, 10-ply E-load tires supposedly built on a stronger carcass to be able to take much higher inflation pressures - in general you can inflate LTs of this size up to 80 psi, if your vehicle requires it - and heavier loads (a 122 load index means 3307 lbs per tire.) The sidewall is therefore built stronger as well, and should be more resistant to scuffing, tears and cuts, the main reason why E-load tires are usually preferred by people going off-road regularly, they can take abuse a lot better than lesser load ratings. The penalty for all that extra strength is the tire's weight compared to regular or P-rated, aka passenger, tires of that same size, which you will notice at the gas station. LT tires are naturally stiffer, so ride quality, handling and often road noise all suffer a bit - again if you compare them to P-rated equivalents. And the pokey speed rating (Q in the case of the Generals) means you can't race them at high speeds on the highway like tires designed for passenger cars or lighter SUVs.
The Coopers are XL (extra load) rated, meaning they were designed to take the heavier load of SUVs and sports truck, as evidenced by their load index of 120, they are usually built stronger than equivalent SL (standard load) tires and therefore can carry more weight and higher air pressure. Land Rover recommends XL load tires for the LR4, since it is such a heavy vehicle. They are not 10-ply construction like E-load Light Truck tires. As such, they are heavier than SL but lighter than LT tires, so your gas mileage should not suffer as much, they should offer a softer and more compliant ride on the road than LTs, and they often have higher speed rating (the Coopers have an S rating, which is pretty much as good a speed rating as you are going to get in an aggressive, XL rated A/T.)
The consensus on the General Grabber AT2s is that they are terrific A/T tires that give BFGs a run for their money while being substantially cheaper, and really excel on the snow (where BFGs and Coopers are not that great.) I considered them as well even though snow is a non-issue for me.