So I have just restarted playing, and picked up my old Necrons, and faced off against Deathwing
On the Necron side,
Imotehk, 3 Wraiths, 2 x 15 warriors and a pair of DoomScythes.
On the Deathwing side,
Belial, 5 TH/SS Termies, 5 regular termies, a landraider and a dreadnought.
Deathwing went first, nightfight stopped all meaningful firepower except the Landraider wounding the Wraiths once. The deployed Doomscythe achieved nothing against the Landraider, nor did the wraiths, and the gaus blasts just bounced.
In round two the Landraider moved forward, deployed Belial and the TH/SS Termies who smashed Imotehk and his squad in one round of combat. The Wraiths due to a 1, 2 and 1 on saves ended up being nailed by the DN's plasma cannon. The deployed Doomscythe immobilised the LR, but was immobilised itself by the Melta.
In round three the TH/SS termies claimed the objective Imotehk was supposed to be holding, and the second doomscythe showed up and nailed three regular termies with it's death ray, while the first Doomscythe finally killed the Landraider and managed to take out one of the TH/SS termies
Unfortunately the game was more or less over at that point. Belial and his squad couldn't get to my remaining troop choice, but fifteen necron warriors are going to get pasted by TH/SS termies, and they shrugged off two rounds of successive firepower.
After a bit of back and forthing in turn four, the game ended in turn 5 with the Deathwing player in control of both objectives, my one remaining troop choice still trying to reclaim their home objective, both my my scythes immobilised but alive.
The Doomscythes performed well, but frankly nothing in my infantry could deal with the TH/SS termies, and the early loss of my wraiths crippled my only counter too them. Getting both scythes immobilised cost me a lot in terms of target aquisition.
It was a fun game, but I still don't feel like I know what I'm doing with my necrons when it comes to ultra-elite armies.