You can always tell those who never actually played this game competitively, or at all, by the ones that bitch about necrons being overpowered.
Yeah they got some nice special rules, fleetwide armor 6. point-for-point, they're also outgunned by anyone, and their 'armor save' has a huge strategic hole in that it's useless against pot-shots.
but the biggest issue is, I could table entire fleets, but the moment it comes time for victory points calculations, I lost.
Their leadership may start at 10, but criticals hammer it down fast. Bracing for impact prevents phasing a ship out, so anytime you are going to get hit hard you have to choose between maybe living, or disengaging it. Generally you have to brace, because you're outgunned as it is, and with the price of your ships (and consequently the size of your fleet) you cant afford to lose any of their firepower.
It's just a poorly designed fleet, and its not overpowered... unless it's fighting eldar.
The only tourney competitive necron fleet I found was one scythe cruiser, and everything else jackals. Only one capital to end up a drifting hulk.