Active mainlining of Allwinner chips is under way.[0]
I only use the devices with kernels from trustable sources, like Debian. The A20-Olinuxino-Micro works already quite good with Debian out of the box. It is even recommended by FreedomBox.[1]
Because mainling for the A64 isn't at a usable state right now, I'm holding back on buying a Teres-1.
[1] http://linux-sunxi.org/GPL_Violations
[2] https://arstechnica.com/information-technology/2016/05/chine...