The Necron HQ choices are interesting tactically in that, much like Imperial Guard HQ choices, they exist more to enhance the army than to directly deal damage themselves. However, with the right match-ups, their HQ choices can be very powerful in combat in addition to their buffing abilities.
Illuminor Szeras is a solid choice, particularly in a low points game. For the bargain price of 100pts, you get a character that has an Eldritch Lance (Str 8, ap2, 36” assault 1) and grants defensive grenades to the unit he is with. He also has a random buff ability for infantry – 2 of which are really useful (+1BS or toughness), the third still partially useful (+1 Str). In a 1500pt shooting list, I would strongly consider him. But, again, Imotekh’s night fight, Lightening and 4+ seize ability will often by more useful; but at a savings of 125 points, you could take a few Solar Pulses or Eldritch lances and mitigate that offset. Szeras doesn’t want to be anywhere near combat, so keep him out of it – or watch him die quite easily.
What do you all think about the Necron HQ choices? What has worked or failed for you?