Should I Buy Z5 or Z5 Premium or wait for the Z6

[AC Question]

Hi! I own galaxy s3 now and I am planning on upgrading to one of the sonys flagships, but I can´t decide which one I should buy. Z5 premium is only 100 euros more than the Z5 so should I pay the extra 100 for the cutting edge 4k or should I wait for the z6 and snapdragon 820? Please help me