After reading so much material on the net, I came to the conclusion that 6S : TSMC chip runs 4-5 degrees cooler and has 10-15 % better battery life compared to Samsung chip. This is only when doing CPU intensive tasks like geekbench stress test. 6S Plus : Samsung chip runs at same temperature as TSMC. This may be due to larger size of phone allowing better heat dissipation. Battery life is more or less the same on both. But many tests put Samsung ahead with 1-2 % better battery life. This may be because of smaller die size 14nm vs 16nm of TSMC. Final conclusion If you want to buy 6S, you can try to exchange till you get TSMC as it is clearly better on there. If you want to buy a 6S Plus, Samsung is better by margin of hair.