As I have no night-diving cert or experience I guess I need to get that in order before I can go do this dive. It sounds like it may be more interesting than the manta-ray night dive. I am however hesitant by the fact that you are suspended above 6000 ft of sea; but as stated above that's not an issue as you are tethered.
If your profile experience level is correct, it may not be the dive for you just yet. I would not say it's "more interesting than the manta-ray" dive, at least not for everyone. The reports I get (I don't do the dive) are mixed, some see nothing, some are overwhelmed, some say it was worth doing once, some say they saw a bunch of tiny stuff but it wasn't really worth it. The manta dive consistently thrills almost everyone. I think the real critter nuts like it more.
For most of the experienced divers I know that won't do that dive, it's got nothing to do with being in 6K feet of water, more to do with inserting themselves into the food chain during feeding hours.