The Militarum Tempestus, not unlike the new Harlequins book, have a pretty small codex and, while containing some very solid units (i.e. good value for their points and decent versatility), struggle with heavy/long-ranged fire support if taken as a pure MT force. To some degree, the Taurox Prime makes up for this, if given the proper build. Despite its relatively weak armor, the Taurox Prime does have several things going for it:
-Transport/Firing Points — Unlike many “shooty transports” (i.e. Razorbacks, Wave Serpents, Devilfishes, Land Raiders, Immolators, etc.), the Taurox Prime can carry a full size squad (i.e. 10 models) AND also has firing ports for that squad to shoot out without disembarking. Even the Chimera has only two firing points in its latest configuration, compared with two on each side (so four total) for the Taurox Prime). This again lends to its versatility, allowing it to transport large or small squads and also still access their firepower without being forced to dismount them. Finally, even bulky allies (like Ogryns, Terminators, and Centurions) can ride inside Taurox, with no limitation like what exists for Rhinos/Razorbacks.
-Firepower — While the Taurox Prime has superior accuracy (BS4) and lots of options (Taurox Battle Cannon, Taurox Gatling Cannon, TLed Hotshot Volleygun), the best load-out in my opinion is the Taurox Missile Launcher (same stats as a Cyclone Missile Launcher) and the TLed Autocannon. Not only does this give solid, 48″ firepower, but it gives very solid options against light infantry (Frag Missiles and Autocannon), heavy infantry (Krak Missiles and Autocannon) and light-medium vehicles (Krak Missiles and Autocannon). I have heard it suggested that a Taurox Prime with this load out be treated as a better armored (i.e. AV11 up front), more heavily armed (i.e. Autocannon instead of Heavy Bolter) Land Speeder Typhoon, since it shares much of the same damage out-put, range, and mobility. Whether used with a pure MT force as with other allies, the Taurox Prime with the Missile Launcher/Autocannon load-out can make for a very effective transport/long-range gunboat, especially when dealing with armies with lots of lighter armored targets (i.e. Eldar, Dark Eldar, Orks, AM, Tau, SoB, etc.).
In terms of survivability, the Taurox Prime’s weak point, I think this can be mitigated in a number of ways:
1 – Using speed/terrain — As mentioned above, the Taurox Prime’s superior mobility enables it to make the most use of terrain. Similar to Dark Eldar, the MT have to use their mobility to compensate for the general fragility of their units.
2 – Target Saturation — While the Taurox Prime can be expensive Transport-wise, it is still relatively cheap compared to the more high end transports, meaning that in a 1750 or 2000 point game you can easily field upwards of 6+ Taurox Primes. As any experienced 40K player knows, numbers of targets have a quality all their own, dividing up enemy target priority and, unless your opponent is very disciplined, diluting its overall potency.
3 – Allied Psykers — Whether Using Force Dome (5++ bubble), Shrouding (5+ cover save bubble), or even an allied DA Librarian with a Powerfield Generator (4++ save for all models within 3″) or the Forewarning power (4++ on a target unit).