I'd be wary of making a RAID5 array with drives that big; you could easily lose another drive from the I/O caused by a rebuild; though if you have backups (you should) then it's probably an acceptable risk for non-critical data.
I'd agree with that. Even 2-disk redundancy these days is a bit dangerous when you're talking about 14TB drives and 100+TB arrays. As is often stated: RAID is not backup.
