I had a set and I agree with everything said here.

1) The chain length does change and you can see your RD taking up the slack.

2) Rotor Rings and BioPace are technically as different as is posibble. They're 90 degrees out of phase with each other.

3) Rotor Rings shift fine if you set up your FD correctly. See this thread/video for details.

http://www.bikeforums.net/showthread...gs)?p=11464684