In the past I have gone with ASUS boards, but I have found that their support over time is terrible, getting BIOS updates with later microcode is a nightmare, it had left many of us to hack/patch our own BIOS images with updated microcode. So far ASRock I have noted have been releasing not just updated microcode, but new features, settings, etc... even for the older boards. They were one of the few that actually bothered to add the Phenom AM2+ support to their older boards.
As for the build quality of this board, it is pretty decent, I wouldn't say its awesome though, the heat sinks on the mosfets are pretty cheap and nasty, fixed with just those plastic spring things.
The issue here isn't that RAM is binned, etc... the issue is that they do not market the RAM at it's real clock, in many cases they don't even specify its 'default stable clock', ie, the real factory clock. So when you are shopping for RAM, unless you do what I was unaware of prior (buy from Crucial), you will be gambling on what you get.
One other thing to note, Micron do sell RAM rated at
1600MHz (DDR4-3200), according to digikey the ICs are around $13.70 USD each. 16 would be needed to make a 8GB DIMM, which would cost $219.20 just for the modules, making a 16GB pack cost $438.4. So unless you are paying that kind of cash for a DDR4-3200 set, you're likely getting overclocked junk.