My general recommendations for players can be found in the new Miracle ticket Guide thread.

As for myself:
I'm holding off on the Miracle ticket until Snow Raphael releases. That means waiting the max of 2 weeks to buy, then 2 weeks to use it. This ensures that my next Jewel roll spree doesn't score me the kamihime I'm going to spend the Miracle ticket on.

My current notable kamihime:
Fire: Acala, Brynhildr
Water (main): Poseidon, Shiva, Triton, Belphegor
Wind (secondary): Gaia, Oberon
Thunder: Tyr
Light: Sol, Raphael
Dark: Susanoo

I'm planning to pick up Cthulhu with the Miracle ticket, followed by SSR Nike then Snow Raphael (who I'll also be rolling on with jewels).