Just RAID 5, and 2 more SATA3 ports over D3 ( A75/D3 has 6, A85x/D4 has 8). A85x is treated as a high-end chipset, therefor A85x boards are meant to have more features and A75/A55 ones. But then that doesn't apply to all A85x/A75 boards. There are some high-end A75 boards like Asrock FM2A75 Pro4, and some crappy A85x boards like Biostar A85S3.
As for onboard Wifi: most of them aren't better than discrete WIFI modules.