I think you must have missed what I wrote: identical hardware.

Once reflashed, they _are_ genuine ASUS RT-AC68U routers, indistinguishable from any other ASUS RT-AC68U, except perhaps by MAC addresses, which can also be reflashed if it ever comes to that.

They happily run genuine ASUS firmware builds, as well as Merlin, and other firmwares. The "merlin guy" has some kind of agreement with ASUS to not promote such. I have a pair of them here (one in use, the other as a spare) running Merlin right now.

Cheers
-ml