A/D conversion

Think about getting a 8 channel preamp with optical output. Then you can make use of the other 8 ports. Optical is digtital already, so no more conversions all the way into your session

Spdif and AES/EBU are basically the same. AES/EBU is balanced and therefore capable of longer cable runs.

You're right, AES/EBU and SPDIF are "basically the same". However, more attention should be paid to the type of cable and connectors used. SPDIF is inherently more susceptible to jitter than AES/EBU...but this really doesn't matter if you pay attention to the cable, connectors, and cable lengths in your setup.

that's cool guys thanks for the replies. cable length is not a problem in my 12x24 home studio. All of my equipment is at the same end of the room. I just wanted to make the best choice.