Well imo a Grandmaster or Librarian is essential to GKs. Terminators, either en masse or just a scoring unit, are realy nice also along with Dreads of any weapon load out. The fact that all our vehicles have The Aegis and Fortitude make them more survivable. Psyfleman Dreads are nasty, cheap, and effective but also somewhat cliche. Paladins won't make you many friends in friendly play, but are very killy if they can make it to the enemies lines.
What I have found that my SM playing buddies fear the most are assaults. All of tge actual GKs carry force weapons, which makes power armor useless and still messes up regular terminators fast. Add in halberds letting us hack down a few SMs at I6+ it just makes it worse. Our Vindicare will make a mockery of you LRs, stranding what ever unit you have inside. Ofcourse this has all got to be chosen and played well or it doesn't work. Regardless of what a lot of people say, playing GKs isn't auto win. I will say this though. Building an effective list at 1k pts is harder than one for +1500.
