So it seem the consensus is that:
Kirin:
Advantages: Looks pretty cool, theoretically powerful (cause it broke rocks ... and stuff ...)
Disadvantages: Takes a huge amount of prep time if no random thunderstorm appears, you better hope the opponent doesn't have a defense they can ready while your lightning dragon is forming in the sky above them.
Rasenshuriken:
Advantages: Looks pretty cool, you can throw it, damages on the cellular level (including chakra channels and whatnot), doesn't take a lot of prep time, spammable, expandable.
Disadvantages: Can be dodged (so hopefully you've already planned for that), doesn't hurt 3rd Raikage somehow (xd).