The Cybook will be the same issue with page turns. it seems to be of similar ergonomic design to the Sony.
I like my Sony, but then again, you could wait until the end of September and see what happens with the Cybook. if it's out, then you can decide which one you want. If it's not out then you can go with the Sony.
One thing is that Sony has announced that they will be supporting Digital Editions wwhereas the Cybook has not made such an announcement.