Generic Haskell Diffs?

According to the communities report there are different generic haskell projects (Jeuring/Hinze and PJ/Lämmel) out there. But I don't understand their relation. Can you use both at the same time? Is one building on the other? Are there adressing different issues? A clarifying sentence or two would be heartily welcome. Cheers, Markus -- Markus Schnell