At this point, I think I've covered the bulk of the units I'll be using, and try to finish it up here.
So far, I've used them in Elfzilla, and they're not bad units.
Amazing durability. T8 means that small arms fire simply does not apply to them, and even tank-hunting weapons are looking at 5+ or 4+ to wound unless it's the dreaded lascannon.
Additionally, Wraithlords aren't slouches in shooting. BS4, a pair of long-range guns, and a pair of flamers mean they can hunt things at any range. So far I'm favoring either missile launcher/scatter laser or missile launcher/bright lance.
In melee, S10, no armor saves, and 2d6 on armor penetration make the Wraithlord adept at utterly violating single targets.
Wraithlords will almost never get cover saves. Armor's at a 3+, which means if anyone has Krak missiles, they wound it on a 4+ with no armor saves. Wraithlords are also a bit tempermental in close combat, with an amazing base 2 attacks on WS4, I4. Now, this isn't a problem if the enemy is S4 or lower all around, as S4 cannot harm a Wraithlord. However, if the unit's large enough and has rending weapons or a hidden powerfist? Wraithlord needs friends.
Wraithsight, as well. They need to stay near psykers or spiritseers to nullify it.
They're durable, and fairly solid gun platforms. They'll absorb a stupendous amount of firepower most of the time, but are weak to high-AP weapons and have to rely on toughness. Then again, T8 is right around the break-point for most high-strength weapons; autocannons/lootas need 5's, missiles and meltas need 4's, and lascannons need 3's.
I'm rapidly becoming a fan of these as anti-infantry platforms. So far I've used them with Shuriken Cannons in lieu of twinned shuriken catapults so they have a fallback for that first 'weapon destroyed' and it's meaningful. That build costs about 135, I believe.
Long-range firepower. Fast. Versatile. That kind of sums up the Fire Prism. It can outrange most anything but Tau rail guns, and harm infantry and vehicle alike. It's also BS4.
Probably won't ever actually make use of the full 60" range, to be honest. S9, AP2 is only so-so at swatting vehicles, and people still get cover saves against the S5, AP4 large blast.
I'm still a fan of this vehicle. It's not very costly, as I don't take defensive upgrades. The biggest gripe I have is that a single weapon-destroyed result is a major de-fanging. However, the shuriken cannon still lets it threaten most targets, and BS4 is a fairly credible threat. I believe that as long as I'm running vehicles, I'll be bringing at least one Fire Prism.
I've yet to run my Falcons so far. I lucked out and found an Eldar Cloudstrike Squadron box, and have built them to be convertible.
They pack a couple of heavy weapons and a half-dozen troops into a grav tank. Moving 6", they can crank out a pair of pulse laser shots and whatever other heavy weapon I bring. I intend to try the Eldar Missile Launcher first, since I can move 6" and fire three S8 shots, or move 12" and fire the Pulse Laser and a plasma missile.
BS3 isn't very convincing. Still, moving slow, it's a good three S8 shots, so still 1-2 hits. 6 troops isn't a huge unit, either.
I'll probably be comparing these to Wave Serpents for some time. They drop the energy field and some seats for more heavy weapons. I could theoretically grab a chin-mounted shuriken cannon, as well.
On Vehicle Upgrades
I'm not really sold on them. They're considerably pricey, at ~35 a pop. They don't protect against the most common ways vehicles go splat, which is to say lootas or melta weapons.
Shaken into stunned? It sounds good on paper, but it's 10 points, and it'll be used 1/6 times on any type of damage. It falls into the category of 'points filler' and I've got other ways in mind.
I'm not entirely sure I'm worried about these any more. I haven't yet busted the tanks out that fast, and if I'm doing it I'm going to be trying to hide them.
I think 24" will usually be enough.