In my experience, Necrons are a poor matchup for Marines, especially the airborne variety, for exactly the reasons in the post. To be fair, you got lucky with 4x crits out of 8 shots, (welcome to my world Mick
), but that is actually only part of the point of the Necron strategy. On average, two Pylon shots at AA4+ TK(D3) will score at least 1 hit each transport aircraft with a 2/3 chance of an outright kill on a THawk, and a further 1/6 chance of a crit on a LC - each such loss taking down a significant formation.
Worse, the main targets for air-assaults (the phalanxes) are off-table - and if played properly, will stay permanently off-table - leaving the Marines with Fearless, RA, Skimming targets (monoliths), that still operate when broken allowing the Phalanxes to assault targets with impunity. The limited MW fire available (usually two Warhounds, 1-2 Landspeeders) cannot destroy the things fast enough, and when broken they escape off-table allowing the Necron player to redeploy them the following turn. This party trick and being Fearless means that ultimately the monoliths have to be shot, since they also do not die or have to move when losing an assault.
Oh, and the 'Living Metal' ability means that they ignore the effects of sniper, MW or Lance, while TK is reduced to (1) meaning that even these weapons have limited effect!! (The E-UK list differs slightly by saving against each TK hit, though that is not a huge difference, especially when you don't have any TK in the army . . .)
When the Phalanxes do assault, they arrive from one portal and escape by another (from the same monolith formation), allowing them to rally off-table. And the 'Necron' ability means they regenerate those units that were killed in the assault. In fact the Phalanxes only actually need to stay on table in the third turn to control objectives, by which time the enemy has usually exhausted its strength.
Pylons are targets when trying to unlock this conundrum by air, but these are deployed by Teleport somewhere in the middle of the table behind the screen of monoliths (risking doom by TK AA) making them inaccessible except by air-assault or teleporting troops in the 2nd / 3rd turns. While the normal 1-2 formations of ThunderBolts can break a Pylon per turn, at the cost of at least one a/c per attack, retreating off-table means that it will rally 2/3 of the time if not destroyed outright. So having two Pylons mid-table means that TK AA coverage is virtually guaranteed around the playable table surface. And the Necron player usually welcomes attempts to destroy the Pylons by other means, since doing that puts isolated enemy targets in range for Necron counter-assaults.
This is why the E-UK leading player (you know who you are
) wipes the floor with Necrons against all-comers, because few tournament armies are capable of defeating the Necron strategy if properly executed.
The main weakness (if it actually is a weakness) is the relative lack of mobility of the Necron monoliths once deployed on the table as they cannot march, which in turn anchors the Necron army. Even so, they can move 30cm a turn and still be used meaning that the canny Necron player can make use of interior lines to catch an opponent who (rightly) decides that his forces really need to get away from the Necron theatre of operations rather than going toe-to-toe. In essence this means that Objective placement and initial deployment is even more critical, since it determines where the Necrons will concentrate and ultimately where the game will be won or lost.
Probably the best (only) option is to play 'sides', place Blitz 2/3 along the long edge and the T&H objectives on either side edge at 30cm from the Necron deployment zone. Then deploy your limited forces far away from your own Blitz and avoid all contact as far as possible. The Necron player can then either choose to chase you (getting out of position), or more likely just settle mid-table opposite his T&H and your Blitz waiting for you to come to him. Turn #3 then becomes a race to capture / contest objectives, starting with attacks on the Pylons.
IF you are lucky and can break one or both of them, you may stand a chance of out-activating the Necrons, forcing them to deploy their phalanxes on table for you to air-assault, but that is a
big "IF".
This strategy determines where you place your reserves at the outset before the game starts (in air-transports, spaceship or teleport), and effectively locks both players into a game that basically turns on the throw of a few dice.
To be blunt, I have not had any good experiences against Necrons with either Marines or Eldar and find them one of the least 'fun' opponents to play against. More than once I have seriously considered throwing the game without playing!!!
![:{[]](./images/smilies/headbang.gif "Headbang")
(And all this from the newly appointed Harlequin Sub-AC) 
