So far I can not complain. The adapter fits both DSLRs beautifully into the slots and even the max. 6.5 frames / sec of the 40D are fully maxed out already at the Ultra cards (max. 30 MB / s). For my purpose so exactly what I was looking for and spared me the purchase of significantly more expensive CF cards.
Too fast card / camera combinations but you should exercise caution, as other reviewers wrote already. Since there can be "excessive demands" of the adapter, which can be felt in clearly reduced in write speed. As has been said to me but not an issue, my station wagon work absolutely flawlessly, so full 5 stars.