When I first read reviews about the 860 when it first came out, they stated the new Samsung MJX chip controller was better improvement. Those benchmarks I posted may not be all that accurate because the 850 has been around since 2014 and the 860 is new (2018) and not many have used that web site to bench the 860 as of yet
3 months ago I had to make a similar decision. Samsung EVO 850 again or EVO 860 (this time 1TB). My 850 (256GB) was reliable so far and I knew their speeds wouldn't be distinguishable (850/860). The 860 was more expensive. I finally bought the 860 to have the new NAND (V-NAND v4 64 layers) with a better wear (as they advertise..double or even 4 times longer depending on capacity). If I'll really take benefit of the new 860 (and it will last longer than the 850) time has to show....if not I actually have wasted the price disparity.
So far reading this Samsung looks like a good choice. Any alternatives, brands worth attention? Best for the money? I am looking for 1 TB capacity. I have an Intel SSD, so far it's good.