Is that 1.5TB on a single drive? If not it isn't going to do you any good as an EHD for your 622/722.
And when they rolled out that DISH-certified version of the My Book, why didn't they base it on the WD Elements EHD? I have a 500gb WD Elements that I picked up at Target for $68 about a month ago on clearance. It has the same AAKS-series Caviar Blue HD inside, but has a well ventilated aluminum enclosure. It just barely gets warm to the touch when playing back stored content, and goes to sleep without any issues when not in use. On top of that, it looks great in either silver or black and is extremely quiet.