It's not one of these is it?
Guess?
The armbian team has made the most progress on the rockchip series of SoC's -- lot of good insight shared in their forums.
My first and brief impression about Armbian was very good. I'm tired of Debian and I don't like Ubuntu. As a result, I can't stay with them.
ATM, my ALARM on 4.4.154 is pretty good... efficiency, performance wise. Main line 4.18.6 could run as well. I'm lacking SDRAM timing data and hence it's no fun to run the mainline kernel performance wise.