I used them, but I wouldn't do it again. They really aren't any more useful in the absorbency department than regular big-kid underwear. They weren't for DS anyway. He would hold it and hold it until he had so much pee in him that he would flood the training pants and the floor and everything around him. The fit wasn't that snug (surprising since Gerber typically runs small). I much prefer the Thomas underwear we got once we were done training.
I neither love nor hate them, but don't expect them to absorb pee like a diaper. As a PP said, they are really no more absorbant than regular undies, so I treat them as such. If you expect them to make it so that you don't have to clean up pee, you will be sorely disappointed.
Re: Anyone use Gerber Training pants?