I believe the performance of these cards is identical. Others might be able to point out differences, but I know of only two.
The audiophile uses a dongle for cable attachment. There are more connectors, but I think they are midi or some other non-hometheater connection.
The Audiophile has coaxial digital out only. The Dio has both coaxial and optical outs.
I have one of each of these cards, and cannot tell the difference in sound quality. BTW, the on board DACs must be pretty darn good. I use the analog out on the Dio to listen to ripped APE files, and the sound is very good.