Signature ability of 4 star champ

Babura0

I have 4* Ghost rider at rank 4 lvl 40, 4* Hyperion at rank 4 lvl 40 and 4*Rogue at rank 4 lvl 11. If you have to choose one for awakening the sig of one if these champs, which one would you choose??

Chadhogan

Hyperion if you need to get rid of your awakening gem but all 3 are still awesome without the sig ability it's a bonus but far from essential imo