I have one of these (and donated one). It's a pretty amazing ball.
There's another charity called Alive & Kicking[1] that makes more traditional balls. The main advantages are that the balls are actually made in Africa, giving people jobs, and the outside of the balls have HIV/AIDS awareness messages on them.
The material feels like the Crocs foam, and I think it's a bit lighter than a regulation ball. It also squishes down more easily; you can flatten it by stepping on it, though it'll pop right back into shape. It also has different bounce characteristics than a regulation ball, I assume due to its weight and materials.
The biggest downside is that the one I got is slightly out of round, though for anyone playing on a dirt "field", it wouldn't matter that much.
Overall, it's kind of incredible what they've been able to do with it. That said, I wouldn't choose to use it over a regulation ball. But if it's all I had, I'd be glad to play with it.
There's another charity called Alive & Kicking[1] that makes more traditional balls. The main advantages are that the balls are actually made in Africa, giving people jobs, and the outside of the balls have HIV/AIDS awareness messages on them.
[1] http://www.aliveandkicking.org/