The chief advantage of the 47Ai is that it has the i.Link digital multi-channel connection for SACD and DVD-A. This is only usable if you have a pre-amp or receiver that supports this format (it's proprietary, and not commonly in use), in which case you can pretty much ignore any sound issues in the player because it'll essentially be acting as a dumb transport.

I believe the DV47Ai also has an extra degree of chamber isolation to prevent vibrations from affecting disc play and to prevent the disc play noise from bothering the listener.

Jeff