I don't think there's much info about them being used on beers. I'm considering using one in a beer this fall. They're quit a bit more $$ than cubes or chips and I'm not sure they'll ass much more than cubes for long term.
Going through life is hard.
Going through life stupid is harder.
The spirals work great in other beverages although I've never used them in beer. They have a very big surface to mass ratio so they work much more quickly than cubes or other chunks of wood. They're not cheap but they are a quality product.