I would be OK with the switch so long as the Exynos SoC used in the S6 is at least as powerful at the 810 while being just as power efficient. I could care less who makes the SoC so long as it gives me an upgrade in performance and battery life.
Samsung has shown that they can make great chips. Their smartphones use Exynos SoCs in other countries, there were just patent issues in the U.S. with LTE. Samsung even made the SoCs for the iPhone 5S and those were pretty powerful, and power efficient, for their time.