Readynas pro pioneer vs WD sharespace

Hello all

I have need of sorting out my external hard drives (currently have 7 TB hanging off my home computer) all full of movies, photos etc

I need to rationalize and protect

I saw an advert for sharespace 8TB and thought "great that will sort me out"

unfortunately I then read on and on and found the readynas pro pioneer
and it is suggested they are not in the same game

so now I am thinking readynas pro pioneer and 6 drives

I was thinking 2 TB drives but I have been told that drives above 1 TB are very unreliable

what do people suggest ???

I was not thinking of building my own system to do all this

am I wasting the money on the readynas?
should I go for the cheaper WD sharespace; uses raid 5/6
so if a drive or two fail I should be safe

can I tie two Sharespace or readynas together to give me more as I already have filled 7 TB and with the raid systems I understand I will have loss due to the backup

thanks