Well k54 has 7 of the top 15 players, however 2 of them are partially in k55.
K44 has 6 of the top 15 players in them, with only 1 player being partially in k45.
With only 2 of the top 15 players on the east side of the world, and only 3 more being partially on the east side, it's safe to say that the east side is the least competitive on the top players side. So the most competitive is a close competition between k44 and k54.