As a WAAG owner, I can tell you that it too mounts to the radiator supports. The only difference seems to be if it mounts under the bumper, or through the tow-hook holes. However... I did use my waag to push my wife's '97 Blazer a few blocks when the fuel pump died, and it worked very well for that. It is a well-made product and was rock-solid until I hit something.
Last Winter I hit a pile of snow in the road and was thrown up on the curb, where my brush guard caught a small tree and spun the entire truck around. Because of how it is mounted, the twisting of the brush guard pulled the radiator into the fan, and the guard itself was pulled about 6" off to the side. By using a come-along, I was able to pull the brush guard back to a relatively straight position, which in turn straightened the radiator mounts. There was no permanent damage to the radiator or fan.
I got about 2 years out of my $400 investment, but I think having the guard in place minimized the damage to my truck. Of course there's really no way to know for sure, it may have in fact made things worse. My opinion is that they are good for any direct head-on situations, but they are bad when hit at an angle.
Of course if you have metalworking tools and the skill, you can make one for under $100 that is stronger than anything you can buy... assuming you have some knowledge of proper mounting techniques and applied forces.