40k: Fire Prism vs. Night Spinner

Sources: here and here

Hey folks! NoName1 here again, to tackle an oft-repeated question for Eldar players: Fire Prism, or Night Spinner?
Now, everyone and their mother has done this breakdown. But I'm going through it myself for my own army and thought I would share the process!
Why make this particular comparison? Because both tanks offer similar firepower, similar points cost, both take up the same Force Org. slot, and they're two of the classic go-to tools for Eldar lists looking to amp up or diversify their heavy ranged firepower.

So, here's the thought process - how are the Fire Prism and Night Spinner different, and how are they similar?

FIGHT!

First off- slot. Both of these bad boys take up the Heavy Support slot, competing with Wraithknights, Dark Reapers and War Walkers (those are the biggest competitors at least) and, of course, each other.

Next, points. The Spinner comes in at ten points less than the Prism, and both are cheaper than any of the options above and compete favorably with a typically equipped Wave Serpent. Part of this calculation is durability, in which both tanks are tied with 12/12/10 AV, 3 HP and being fast skimmers able to Jink (usually with the bonus from Holofields). Although Wave Serpents are decidedly tougher than either, because of the Serpent Shield.

If only there were an army of hover cats...  No. No one wants that.

Third, role. The Spinner is Infantry focused, with plenty of threat to light and medium vehicles to boot. The Prism, by contrast, has an opener for every can. This gives the Prism a leg-up in terms of filling gaps in many armies, but makes it all the more critical to keep Target Priority in mind during games. You could mistakenly take that one S9 Lance shot (and miss, wasting a turn) when nuking the blob of Ork Boyz on your doorstep was the smarter move.

Speaking of, lets get right to guns-
The Night Spinner has a 48" range, S7 Large Blast with a forgettable AP5, Monofilament, and - most importantly, Barrage. That's solid, especially since Monofilament makes it S8 vs. Vehicles and low-initiative armies such as Tau and Necrons. Also, on a to-wound or penetrate roll of 6, it's AP1. Nice!
The Night Spinner also has a second firing mode that's Torrent, and therefore Ignores Cover.
Oh! And the Night Spinner's main gun also has Pinning. Back in 6th Edition, that was a given as all Barrage weapons automatically caused Pinning. In 7th though, it's a nice perk that the Night Spinner still has Pinning where many tanks lost it.

The Fire Prism has three firing modes (60" range each): S5, AP3 Large Blast, S7, AP2 Blast, and S9, AP1 Lance. As such, it boasts far better AP shots, and an anti-tank shot that will penetrate any AV on a 4+, glance on 3+.
Both tanks can also take the underslung Shuriken Cannon, but in general that conflicts with their battlefield role a bit (being short range, requiring LoS, and being infantry-focused).

One will come out on top! Thanks to Lt. Coldfire

So, what to take?
Both tanks suffer from the same problems Vypers and Serpents do, in that they're likely to have to Jink to stay alive and thus being limited to Snap Shots. Only it hurts them both more, because of being largely Blast/Template shooters, or getting only a single shot. A skilled player could easily keep either tank Jinking for most of the game, making them great big paperweights at best.

There, the Night Spinner has the advantage, because it can fire without Line of Sight. In a game where line-of-sight blocking terrain is available (to either side) the Night Spinner would really shine over the Fire Prism - both by being able to hide and still shoot, and threaten those enemy units that try to hide themselves.
The Fire Prism has the slight advantage (mentioned before) of having that single Lance shot. But having a single shot that hits on a 6+, while making for some great moments if it does work, is in most cases equivalent to no shot at all.

Then, there's the elephant in the room: why would I take either instead of another Wave Serpent?

Spam spam spam spam...

The short answer is to have a wider variety of tools in the list. The long answer involves a lecture on trying to avoid repetitive spam lists, but I'll spare you that one.
Simply put, the Wave Serpent is practically perfect. To the point that many players consider it broken. I don't disagree with that. I also still take Wave Serpents, both because they are SO GOOD and because, if you want a transport (and not to lose the HS slot to a Falcon or take Allies), you have to.
That said, even the vaunted Wave Serpent can't do everything. Its shots, for the most part, have no AP (when run with the typical Scatter Lasers on top), it can't tackle heavier tanks, and it can't shoot at targets that hide behind walls.

And that leads us back to the first, and final, question: Which is better?
Well, they're both better for different roles, etc, blah blah blah.

In my case, I will test both with proxies, but I'll give extra weight to the Night Spinner. Why? Because it has the coveted Barrage, and that's something nothing else in my army has. Second, it's a solid answer to mobs, which is something my largely elite list could use help with. Lastly, it has a (granted, situational) weapon for Ignoring Cover. In 7th edition, that's pure gold. Throw Crystalline Targeting Matrix on that sucker and if something REALLY needs to die, zip the spinner across the field and lay into that cover!
The Fire Prism is a better answer if I have trouble with heavy armor. But really, in most cases a barebones Wraithknight is far superior (you pay for it in points, but still) for taking on heavy armor. I also have both Fire Dragons and Swooping Hawks in my typical list, so armor isn't my problem. My army relies heavily on mobility and being able to hit my opponent where it hurts, and that doesn't work when they're hiding in the bushes. So! Night Spinner it is!

How about you? Fire Prism or Night Spinner?