since this is a good thread.. and just pm to ask about ac ryan hd2..
maybe can ask other expert.. i am currently using ac ryan essential and would like to upgrade to ac ryan hd2..

any idea if what is the difference between this 2 model?

or any recommendation based on below requirement.

able to slot in internal hdd 3.5" sata hdd
do not need 3D
able to support most video files and high def