Started a 2nd char a FemShep Infiltrator yesterday

I like Neural Shock early on an infiltrator as well, since it is a very rapid cooldown organic CC power.  It overlaps a bit with Incinerate, since both will CC organics, but Incinerate has a longer cooldown and of course deals real damage.

Slam fulfills a similar role with a similar cooldown, but it can prime warp explosions.  Window is small at rank 1 though.

Stasis is a good CC power for mini-bosses, and there is a glitch where targets take extra damage when hit as they fall out of it.  Also fairly uncommonly enemies will fall through the ground or just outright be killed by it.

I don't tend to take the ammo bonus powers on Infiltrator, but AP or Warp aren't too bad. Ammo power damage is calculated off of weapon base damage before weapon upgrade bonuses (for every weapon class except assault rifles), so in effect the ammo damage gets weaker as the game goes on and you pick up upgrades. Level scaling in this game makes theorycrafting a bit of a pain, and I can't remember specifically what level Warp Ammo vs what level upgrades or cloak you need for specific Collectors. Essentially every basic enemy has 150 points of protections (be it shields, armor, or barrier) on Insanity, but their damage taken is scaled by level from 1 to 30.