I'd have to pick Cryogonal, though I despise both of them. Sigilyph is just too awful, while Cryogonal is bad, but tolerable. With Sigilyph, you have a jack-o-lantern made of wood, with forks for arms and a tail, a giant black eye stalk extending out of its' head, weird skeletal wings, and spikes under its' eyes just for the hell of it.
With Cryogonal you have a robotic ghost snowflake.
No. just no.