I'm still running most of my Crypteks as Transmogrification, using the Tremorstaves in conjunction with my C'tan's Writhing Worldscape. These guys hang out in 5-man Warrior squads and try and spam out as much dangerous terrain as they can. Of course it's most effective against bigger squads, though a few lucky rolls can make a solid dent in a smaller unit. On top of damaging units and immobilising vehicles there's the added bonus of slowing enemy movement as they struggle through difficult terrain, making it a good way to break up the solid line of an enemy advance.
Fun as that all is, I've been starting to wonder about the potential for different setups. Most of these would require a pretty major change in tactics, moving my Warrior units from the back of the board to the front lines where they could make use of the 12" range and Template range staves. Of course I could turn some/all into Destruction Crypteks for good tank-busting and heavy infantry killing joy, but that would have them spending a lot of the game targeting only tanks when my actual Warriors want to be gunning down infantry. On the other hand it wouldn't be a total loss as Gauss weapons have the potential to add that little bit extra help on the anti-tank front.
Of course Crypteks don't just go in Warrior squads. I've got a Veil of Darkness Harbringer of Despair chilling with my Deathstrikes so they can hop about the board doing cheeky multi-marking. I've also experimented before with taking the Destruction Crypteks as a single Royal Court and obliterating any armour that gets into range. If I did try that tactic again I'd want to consider taking fewer squads of Warriors, but in groups of 10 or more with Res Orb Lords to make them uber resilient.
So what does your Royal Court get up to?