I don’t actually have either, but Equestor will be decent at the lower end of gameplay or vs bases with weak storm and mage towers due to the lightning familiar’s tower priority. Thunderbolt will also tear through undefended bases with weak towers as well. It’s pretty much a more aggressive version of Kinnarus.
Kirin’s utility will really be with preventing mage drain and anti-projectile, which is good for invader bases, haha.
It really just boils down to progression prizes, the stuff not directly involving dragons, and how much more you’ll get from finishing an entire dragon line cheaply (claim before the discount ends) vs a some prizes on Equestor. And there’ll always be more dragons in the future.