On a 1v1 map, I wouldn't touch it.  Of course, I very very rarely get this high in the tech tree in a 1v1 scenario.

In a team game, this is extremely important if you're doing phase stabilizer jumps across the solar system.  That extra speed means a lot on huge maps where a phase stabilizer short-cut (or back-world Kostura attack) could leave your fleet jumping for several minutes.

OK, thanks for clearing that up, guys.  Next time I play Vasari in a game where I end up being very rich and have lots of phase stabilizers, I'll consider researching that.  I can see how it could be very useful.

The way to use it is you set up a phase stabilizer on a dead asteroid (or some other planet) on the far side of the solar system.  This allows you to quickly redeploy your fleet to win a 2v1 battle quickly, then get back to defend yourself.  Obviously every second counds in a situation like this.

The problem is that it's a double-edged sword.  If the enemy fleet is there defending, then killing these units is trivial and it can level up the enemy's capital ships.  If this is a long and drawn-out game, this can actually end up being an advantage to your opponent if you aren't careful.  That's why insurgency is generally considered a very questionable tech.

Annoying in the short-run, but in the long-run the enemy empire is going to need to starbase spam to defend against novaliths anyways at which point this ability is just a joke since it's no threat at all to a starbase.

The problem with the novalith is that starbases with the correct upgrade (auxiliary government for TEC, enduring devotion for Advent, and enforced loyalty for Vasari) can protect the planet.  The novalith blasts will still kill population, but the enemy will keep control of their planets.  The problem is that if you can afford a large number of Novaliths to deal serious damage, the enemy can afford a large number of starbases to protect against them.

The Advent deliverance engine gives your fleet extra punch in battle, allowing you to break stalemates and win the game.  The Novalith can deal economic damage to the enemy, but it won't weaken their defensive position, so long-run it's not nearly as devastating as it may appear.

but theres no way to tell which planet the novalith(s) is going to fire on, surely its not practical to put upgraded starbases at all or most planets? how would i sustain a fleet and research?

admittedly tec can stop novalith shots with planetary shields, but vs other factions isnt it fairly good to deny tax and force the opponent to redevelop every bombarded planet?

Well endgame (which is when novaliths appear) it is easy to wait five mins after the radiation 'cools' and then totally rebuild the planet infrastructure. You also didn't disrupt trade income which is the number one source of revenue. Sure if you 8-10 novaliths it is gg unless the enemies have SBs with the auxiliary govt or equivalent tech. But they don't need to cover all planets to be in business just some key ones. Knocking out a key planet with several frigate factories is nice but the other player can in principle try to adapt.

There is no adaptation for 11-12 synchronized Kostura cannons. Your defensive positions crumble. Your fleet dies. You die. Basically it is all over but the screaming. RA has some utility but since the cost is so high you are better served with even a few Kosturas and a larger fleet.

Stunning phasic traps is so key when you have to fight an Orkulus backed up by fleet. You time your shots, stun the grav well (like subverters covering hte whole grav well) until you can take out the key structures and kite the Orkulus. His fleet is standing there picking his nose while you have unraveled his fortifications. A single Kostujra shot or two in addition to your subverters and grvity warhead is also great at cutting off an enemy retreat which is really deadly imo. This doesn't even account for the shenanigans you can pull with an instant phase stabilizer node. Like jump behind lines, frag a planet, when pressed by a large defensive fleet just shoot again and jump back to one of your phase stabilizers. You can retreat easily since you just stun him when he shows his face. If the system is no longer hostile just scoot one system over and then do the trick. Voila! All you need to do is time it.

Now if deliverance engine stacked that would be pretty sweet. But it doesn't so it stinks.

I will admit I have never been on the business end of a Novalith barrage. But as long as I SB my key worlds where I am producing ships why would I SB all my planets? I have a few efficiently placed colonizers and if I lose a couple planets to Novaliths I wait till the dust settles and recolonize. Yeah it sucks but I don't need to SB every world. Yeah I lose income but you won't be able to colonize due to culture. And most of my income is from trade anyways.

I am assuming I also have a fleet, right? Also that 72K could be better spent on more fleet or even Kosturas if I am Vasari. Now if you are dominating me in culture then yeah you can try to also grab the planets once the radiation dissipates. But you aren't Advent so I should be able to hold culture (unless you are spanking me down anyways and so what is the point of the Novaliths?). Of course if you have six or more Novaliths then yes I am screwed. But then what was I doing while all this was going on?

I am sure Novaliths are helpful especially during a stalemate. I can also see how it is a great prelude to a full invasion just like Kostura is a great icebreaker to jump into a hostile grav well. Like you said you don't need to specialize in planet busting because you have one with the Novaliths (you often need two close shots to humble a non-roid, right?) Personally though the game seems so nonlinear that even a slight advantage gets magnified quickly. I suppose in some cases the tipping point could be Novaliths but I suspect that there are a lot of different alternatives to also lead to victory.

Lets reverse it you take 3 Novaliths and I'll take 3 Kosturas. Which is better?

Again in full disclaimer I have never been hammered with either Novaliths or Kosturas whether by AI or human players. Any multiplayer game I have been in (not many I admit) is over before these items are reached. The exception was one team game where a pocket Vasari opponent said "I have Kosturas", took a couple of potshots and my team quit.

You don't have to SB every world to protect from Novaliths, just the Terran, Desert, and if you get around to it, Ice worlds.  Your late game economy won't even miss the loss of asteroids or volcanos, because the worlds themselves provide very little income, the benefit is in the orbital structures (which you have hopefully built out).  If the world is not frontline, you can also throw some trade or economic upgrades on a SB in addition to Auxiliary Govt and it will eventually pay you back the cost for building it if the game drags out.  As long as your crown jewel worlds are protected, the Novaliths are an annoyance that cause a small amount of economic damage and maybe halt local manufacturing.

Bottom line, Novaliths can be useful, but make sure there are worthwhile unprotected worlds to hit before you sink a lot of cash into them.