Just got the system yesterday.
I am also using 4 x ST31500341AS, however already with the updated CC firmware
I updated the 343 to 1.02 firmware.
The first time I tried to configure the system as RAID 5, I had the same "stuck at 94%" issue others have reported. After I rebooted, I reconfigured them again and all seemed to work.
However, my Volume1 is only 94GB in size. The Status screen reports that all 4 drives are present and are 1500GB in size, but the total usable space is 87GB. I have reformatted, reconfigured, pulled the drives and wiped them--nothing. I have read through many of the posts here and haven't seen anything--but will continue to look.
I have a NAS with 6TB of disk--and less usable space than my iPod.
Any thoughts?