I used it a lot of times, before the Draft FAQ came out limiting it to only the Transcendent C'tan.
Cryptek with Veil of Darkness and Phase Shifter
Cryptek with God Shackle or Solar Staff and Phase Shifter
Gives the Nightbringer the needed mobility to get in range to abuse his 12" power. God Shackle or Solar staff gives you the protection against shooting that you need. God Shackle gives the whole unit T8, instead of T7, which prevents all ST4 or lower guns (few exceptions, like Necron Gauss) from getting a To Wound Roll. Solar Staff gives you a turn of minor invisibility, preventing blasts and templates, this choice is dependent on the possible opponents.
The 4++ all around and 4+++ Reanimation on the Crypteks, even against ID, let you spread the wounds out a little if they get in. Remember to "Look out sir!" on 2s for the Crypteks when a ST10 wound would ID them, putting it on the C'tan.
If they are using the Draft FAQ, don't bother with it. The Transcendent C'tan is not worth using like this.