I'm not sure which Cryptek is the current Internet favourite. Maybe the Harbinger of the Storm? Either way, I like afew Destruction Crypteks in my army. They can deal with vehicles, they add some ranged threat beyond the standard Necron 24", and they bring some high strength low AP for chipping away at Terminators, Monsterous Creatures or whatever. They have nice utility. Plus, huge laser-lance gun-cannons! That's always good, right?
Anyway, I have 3 in my list and here's the second.