a) a57 is the "beefy" version of a53, it's significantly faster in raw performance so this should stomp an rpi - here's ARM's performance numbers at release: https://community.arm.com/cfs-file/__key/communityserver-blo...

b) above the HDMI is displayport

c) usb is 3.0 all around, great for NAS-style devices

d) production module (for final product) uses 16gb emmc, whereas the devkit is microSD like rpi