Their new WD RE2 750GB SATA unit is more or less the same as their existing 750GB offering, with the exception of a few new features intended to increase the resilience of the drive. That leads to them giving it their “RAID Edition” label, along with a higher MTTF rating than comparable drives.
For the size and certification, the drives are not all that expensive. The listed MSRP for these 750GB units is $265, more than standard 750GB offerings but not by a terrible lot. The press release does not indicate when, exactly, the new units will be available.