I actually considered playing Necrons too,
OP. The silent march of death was appealing to me. However, after playing through enough of
DoW: Soulstorm and really seeing how brutal
DE were, I had to jump in.
The fluff and looks is what sold me. The idea of a force of nihilistic hedonist pirates sounded so appealing to me. Commorragh is amazing too, I really hope they flesh it out more in the new dex.
As for what to expect? If the player is actually making a competitive list, lots of Dark Lances/Blasters and Raiders. The parking lot of doom. Raiders can be included with any Warrior or Wych/Grot squad, so theoretically there can be 11 Raiders on the board, (
HQ's can be mounted too)and that's not including Ravagers. The raiders themselves are basically coffins though. 10 Armor, open topped skimmer... won't take much to blow them to pieces. However, they can move all out 24 inches and get a 4+ cover save. If the
DE player feels bold he might just throw all his Raiders to your face and get lucky rolls and have his army assaulting you by turn 2.
Warriors can equip Dark Lances, 2 per squad if they foot slog or just 1 if they go on a raider. Blasters are like mini
DL's in that they only have 12 inches but are assault 1. Archon+Incubi *will* wreck your day, these are melee monsters. Wyches are basically there to tar pit shooty units and they can get random buffs per game based on what drugs they inject. (One buff lets them assault 12 inches - beware!)
DE is a very finesse army. They have to use their wyches to tarpit shooty threats and have the Ravager/Warriors/Incubi pick off targets. I consider them a mid-range target priority army. The downside to all this firepower and mobility is that we are squishy. Warriors only have a 5+ armor save and 3 Toughness. Wyches have 6+ armor save and 3 toughness but get a 4+ invulnerable in melee, which is why they are good at tarpitting.
We have no psykers despite being Eldar, and have a wargear that can flat out KILL any psyker on the board, but it's rarely used.
There are other troops but they are so outdated players rarely use them anymore. You'll be lucky to see someone field Scourges or Hellions.
As for painting I've just begun painting my army. Grimdark works just fine for
DE. Besides, Necrons are always brass or silver in some form
What I plan to do is paint each squad differently to help me discern them on the table. So one squad will be brass+black+bonewhite, another will be light/dark purple, another will be red+black, etc.