A difference between the AK77 600 Max and the AX4C is the RAID implementation. On the AK it is IDE Raid while on the AX4C AOpen has chosen to go with SATA RAID. Personally I think SATA RAID is a better choice seeing as how the highest performance SATA drives, the Raptors from WD, are only available through SATA interface and to be wanting to RAID usually means that you are a performance nut. That being said, the 4 SATA ports is very generous