I think that the Areca controller is better than the adaptec becase of the out of band mgmt.
But the Adaptec card supports RAID5EE + 1EE. Lastly, the Adapec HBA takes FOREVER to boot!
Oh yeah, you can even update all the firmware on your drives using the Areca controller. But you have to have the latest SAS firmware for the controller. Managing Areca firmware is a pain though because you have so many different components (e.g. BIOS, firmware, SAS)