Not too sure about the lack of hangover, but several producers in Champagne and Bordeaux are producing superb organic and biodynamic wines. You could of course question whether it is the organic techniques or the fact they are caring about their raw products that is making the big difference.
I would say the hangovers from organic alcohol are not as bad - think though that it is more to do with the sulphites and other chemicals not being present in the wine. I expect it will still dehydrate you as much.