Written by T0nkaTruckDriver, Edited by T0nkaTruckDriver
The latest editions to the Tau Empire, the Vespid are a valuable tactical asset in their own right.
Where Do They Get Those Wonderful Toys?
The Neutron Blaster is second only to the Rail Rifle in our list of infantry-based Marine killers. Even without Markerlight guidance, it tips the scales at 0.0208 Meq kills per point... almost twice that of Firewarriors or Stealth Suits. This insane killing efficiency is partially offset by their short range meaning that they'll likely be unable to fire every turn, effectively reducing their overall efficiency over the course of a full game. Whether or not Vespid are a "worthwhile" unit is entirely dependent on how good you are at keeping them within 12" of a suitable target without getting shot up or assaulted.
The Glass Cannon
Although able to dish it out in the shooting phase, Vespids have little to no ability to take return fire... an unfortunate circumstance when coupled with their 12" range guns. The ironic thing to remember is that although Vespid carry weapons uniquely suited to killing Marines, those same Marines carry weapons devistating to the Vespid as well. The Vespid therefore make the most sense when used in a Mont'ka role, finishing off an already wounded squad thereby minimizing the chances of excessive return fire.
In order to preserve your Vespids, it quickly becomes apparent that terrain is your friend. Their Skilled Flyer and Fleet of Wing special rules allow them to maneuver from one terrain peice to another in order to position themselves for the aforementioned Mont'ka. When you do finally jump out to fire, do it in such a way so as to minimize LoS to other enemy units.
Assault may seem a viable option on account of their respectable I5, however don't get too excited. Most of the points you've spent on this unit are on account of their powerful Neutron Blaster, and each turn spent locked in close combat is a turn you aren't shooting or maneuvering for shots. Obviously the best circumstance would be if you could assault with the Vespid, win combat but have your opponent pass their morale check, and then finish them off during your opponent's assault phase so you're free to move and shoot again in your turn. However this set of circumstances is just too convoluted to be relied upon. While their high Toughness and Initiative may make them seem decent in assault, the best place for these guys really is as shooters.
Return on Investment
As mentioned above, the only way the Vespid are going to prove worthwhile is if you're able to get shots off without taking significant return fire. Obviously the easiest way to accomplish this is by holding your Vespid in reserve out of LoS and using them as an emergency responce force, only jumping out to engage imminent assault threats, hopefully using terrain to limit LoS to the remainder of your opponent's army. In this role, their movement buffs allow you to maneuver to counter fast assault units threatening your lines. If your army list includes static and/or slow(er) elements such as Broadsides or on-foot Firewarriors, you can bet your opponent will attempt to tie them up in assault and having a unit of Vespid on hand as "firebase bodyguard" isn't a bad idea.
However, if facing off against a mostly shooty force in an all-comers setting, getting use from your Vespid becomes a bit trickier. While difficult on account of their short ranged guns, pulling this off is not impossible. Clever use of terrain is obviously the simplest way to limit LoS to the remainder of your opponent's army, however there are some tricks you can use if you're fighting on planet bowling ball and/or if your target squad happens to be out in the open.
Using Landed Vehicles to Block LoS
This seems what the Disruption Pod was made for. By landing a D-Pod equipped Devilfish in the center of the table, you give yourself a made-to-order piece of LoS blocking terrain, which while not quite as durable as a fast-moving skimmer, can still count penetrating hits as glancing half the time. You can now hop your Vespid (or a JSJ unit) in behind the vehicle to support your other units without fear of annihilation in your opponent's shooting phase. A simple example of this is shown below.
Using Close Combat to Block LoS
Similarly, a swirling melee between size 2 combattants can be used to block LoS to a small unit of Vespid. For this purpose, Kroot serve well on account of their large unit size. Move the Vespid and Kroot into position, fire the Neutron Blasters and then assault with the Kroot. Be sure to make clever use of your pile-in move to block as much LoS to your Vespid as possible.
Another option is to use a Vectored Thrusters equipped Commander for this task. The disadvantage here is that the combat will be smaller and hence will not block LoS as well, however the upside is that the Commander can leave combat at the end of your opponent's assault phase allowing the Vespid (and Commander) to get further rounds of shooting in against the target.
In conclusion, Vespid are a deadly yet frighteningly fragile resource. They compliment a mobile force well. That being said, they don't offer any new tactical options. They're more efficient at killing 3+ saves than just about anything in the list, however they pay for that efficiency with a lack of range and durability. In order to decide if Vespids are right for you, you first must ask yourself how badly you really need additional 3+ save killing power and then whether or not you're willing to make the necessary sacrifices to get it.