The table below shows the average amount of kills/wounds caused by the three variants of the Moray's stats discussed in this thread. The Super Heavy Tank column shows average hull points destroyed rather than vehicles.
To standardise results, this shows damage caused by 8 of the version of the Moray version Onyx posted early in the thread (cost 2400), 7 Flo'ka Moray (cost 2450) and 8 Vior'la Moray (cost 2400). (I labelled it Onyx Manta by accident

)
Because this is just for internal balance, it uses raw stats (without affect of sustain, movement and markerlights)
The best choices against particular targets are highlighted in red, good choices highlighted in orange. Weapons with the ability to engage at long range (75cm+) are obviously superior choices to the average 45cm.

Conclusions:
The old proposed Moray (championed by Onyx) is best vs Guard, Marines, Predators and LV. Joint best vs Russes (4+RA) and good vs Terminators
The FloKa version (Dobbsy) is best vs terminators, and good vs all other targets
The Vior'la version (Matt) Is best vs Super Heavy Tanks and joint best vs Leman Russes, while inferior vs all other targets
While it wasn't a subject of the test,
the Manta is comparitively weak vs all targets when its price is factored in. (if it's the lists super heavy killer, then 2,600 pts worth of Manta kills about 8 HP of SHT, while 2000 pts of Shadowswords (15) kill about 20 HP, for example)
The reason for the version of the stats I have been trialling on the Moray are because my opinion at this time is that Tau are
excellent vs Infantry, moderate vs tanks, and weak vs reinforced armour and super heavies due to reliance on shooting without the back-up plan of assault most armies use to clear armour.
If that is the role the Moray is to fill, the chart backs up the idea that the Vior'la version does it best since it is (slightly) better vs tanks and SHT than the other two, and worse vs everything else. The rest of the Tau list is good vs 'everything else'

The question then is whether that is the correct role for the Moray or whether it is intended to be more of a multi-role generalist War Engine, in which case one of the other stat lines would probably serve it better - probably the one Onyx posted.
I'll try compare it to the damage out put per point spent of some of the common WE since I anticipate that question coming up.
In the meantime, opinions are welcome!