At least R7800 is very easy to flash, and has a good u-boot TFTP recovery mode.
R7800 is additionally much more enthusiastically supported here and has wider user base.
- Main support thread: Netgear R7800 exploration (IPQ8065, QCA9984)
- community build (from me): Build for Netgear R7800
I have R7800 and I am happy, so I am naturally biased 