I use Kakao on the Lumia 920 in Korea, as well. It looks better than it does on other platforms, but doesn’t work as well. And as a desktop Mac/Windows/Linux & mobile Nexus 4 & 7/iPhone 5 & Retina iPad/Lumia 920 user, I would like it if Kakao didn’t tie my account to one device, and make it such a pain in the _ss to move from one device to the next.
I mostly use facebook messenger because I can pick up the conversation from any device. FB Messenger is the only thing that has kept me on facebook, truthfully. Their acquisition of Beluga brought me into the fold, and their revisions have kept me there. Kakao seems to be content to sell me a bunch of stickers and knock-off services instead of bringing their core messaging application up to par with FB Messenger or Whatsapp. Hell, even Naver Line is better from a functional standpoint.