The biggest issue since the release of Raiders, until EUK changed Living Metal at least, has been Destroyer pricing. The original playtesters are adamant that they are broken at around 300 points, while many others claim they are overpriced at 375 and leave them at home.

This might be because those who tested Raiders used Destroyers used them in a manner most other people don't (perhaps because you're more careful with a more expensive formation?). Or, it could be because countermeasures have been discovered which nobody was aware of during playtesting. So:

When you use destroyers, how do you use them? Do you deploy them, or send them out of Portals? Do they soften up formations and support Assaults, or do they target formations they can cripple just through shooting at them? Or are there other ways I'm not aware of?

When you face them, how do you handle them - throw some stray shots at them, focus them until they are wiped out, engage them, what? Are they a problem or can they be ignored? Do you fear Monoliths doubling and then Destroyers retaining for an Advance action that can target units 90cm away from where the Monolith started?

Ok, to break the silence...

Having pushed around Necron minis for about 10 games now, of which five-ish(?) featured destroyers, I'd nevertheless like to give my modest contribution. Stream of consciousness ahead...

I always played them in a formation of 6, adding a lord, thinking that they always will be awarded BMs and every BM less is a significant boost to firepower. As much as the idea of meatshield wraiths is titillating, they would cost way too much. I have composed the formation both with all 2*4+/6+ guns and with exchanging two for at3+ guns - I might prefer the latter, as it has the choice of which guns to keep silent while the formation has a few BMs, and IME destroyers will indeed always be fired at if there is an opportunity, as every BM (and casualty) makes a significant difference, a bit unlike with other Necron inf. (Choosing which guns will rise back up is neat too.)

With that in mind I always keep them in reserve. I wait for the moment that most anti-destroyer options have already activated; more often than not, I think, I didn't activate them at all until turn 2, when I had closed the distance a bit. (I tend to teleport most or all of my units aggressively in the fore, save for pylons.) As the destroyers finally need to step forward to start earning points it's a tough decision, and always rather situational, what they will do...
Because if they can, they will pick a meaningful, low-danger position and work from there, ideally destroying one weak activation that thought itself safe. (I think one of the most important uses for destroyers is using their high-volume, decent-range anti-infantry/LV firepower for whittling down your opponent's activation count... something that other Necron units are not effective at.) To create a low-danger environment, anti-air support from pylons is rather essential. An opportunity to enter a portal with one move is very welcome to keep them in the pace of the battle.
Peripheral safe spots won't do at all... they will need to go all-in, ideally advancing out of a portal to shoot up an important formation and immediately offering fire support to a phalanx that retained initiative to perform an engagement (and possibly taking up a position to cover the destroyers somewhat).
I'm wary of engaging with the destroyers themselves because accidents can happen... unless there is no safer option. Most of the time a phalanx will do fine, moreover, usually if a phalanx could not reach the target from a portal and destroyers could, the destroyers would be either stranded too far forward from the rest of the army (and probably get mauled), or too far in the flank to remain a properly meaningful threat for the next turn (if they had picked a safer route, that is). Even needing to double move is devastating to the formation's potential especially if suitable targets are in cover. That being said, the potential of warrior phalangi beyond 45cm is (of course) zilch unless there are portals in position...

I do think they definitively have a place in the army list with their rules being as they are. But they are rather dependent on the table having suitably lavish amounts of terrain (as glasscannon elite units tend to be), hard to use (really now?) and the price is a bit high... I could see them costing, as a compromise, 325-350 points with a free lord included, but hardly below that? If they are in danger of becoming cheap enough to be spam-able, one solution could be the enforcement of a simple 0-2 restriction. But cheaper destroyers should definitely remain a support formation.

I've always tended to use my destroyers quite aggressively and my monoliths quite conservatively. I'll often throw the destroyers out of a portal to harrass a unit that may become a threat to my monoliths later in the game, like Speeders and warhounds or to pick on and destroy garrison units to increase my activation advantage later in the game.

I generally pick targets where the return fire from nearby fms is not going to be sufficient to kill them all. A warhound for e.g. attempting to avenge a fallen brother will often break a fm of destroyers and not kill them which is ideal. The high speed of the destroyers allows them to flee to safety, either hiding or going off board through a portal, their allotted turn 1 task complete. The SC re-roll is generally reserved for rallying broken destroyers turn 1. Turns 2 and 3 really see them come into their own, marshalling out of a portal to support an engagement, picking on broken units, placing BMs and shooting stuff up and engaging the bejesus out of whittled down units, once I have the desired activation advantage - and of course getting onto objectives using their higher than average speed.

They're a good unit but too costly, even at 300pts to spam and if they were any more expensive would lose their slot to Obelisks every time due to lower speed, less armour, lack of fearless & TRA and lower range.

I never use a lord with them as this creates BTS issues, although at 4000pts I probably would.

I have used them in every game I've played (6 or 7) with necrons. They absolutley have their uses. They're great for killing LV targets (since they usually hang around in cover) and also for some late turn 3 objective grabbing/contesting.

I do think they are overcosted though in netEA. I would personally dropp them by 25 (or perhaps even 50) points more. I like the Lord option and right now at 375 points, I think a upgraded phalanx for the same cost is better value.

cheers

Is there anybody who think they are priced correctly who would like to share their experiences?

I think they are priced correctly

most often I use them to prep a target for a retain assault with a phalanx.

In an army that has mobility as its only drawback, Destroyers are the answer to the Necron player's problems. Fast, lethal, great armor, regenerating, and able to capitalize on portals, the Destroyer is a killer unit. These are flanking formations, able to 'herd' smaller formations and harass larger ones while Phalanx take the brunt of their opponent's punishment. Position these on the back of the board when coping with large garrison formations. Teleport in a heavy phalanx formation to activate their overwatch, take the punishment, then move in with the firepower of the Destroyers. This keeps them untouched from attacks and unleashes full power against an already pummeled formation. If the garrison hasn't broken already, it will be in a dubious position where it is ready to be obliterated by an assault later in the turn or on turn 2.

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