I bought one and played with it over the holidays and there are a ton of OS options now. There's Armbian support now, which wasn't around at first, and it seems to be very stable and feature complete. The board is significantly more powerful than a Pi 3 with emulators and compiling and just about everything.

I had so many problems with Tinker OS and I wasn't the only one. Never tried Armbian so maybe it's better, how's the graphics performance with that?

You can actually boot Raspbian (or probably any other ARM OS) on Asus Tinkerboard - you only need to copy some files to /boot (including kernel) from TinkerOS and several kilobytes of bootloader after partition table.

(That way you can prepare image that boots both on RPi and Tinkerboard)

That sounds cool! Does the tinker board hdmi/audio work when booting raspbian?

HDMI works (only kernel support and xserver-xorg-video-fbdev for Xorg is required), I haven't tested audio.

Example hybrid image for Tinkerboard and RPi is here (based on Ubuntu): https://files.husarion.com/husarion-core2-ros.img.xz (unfortunately the build scripts are not public yet)

I can vouch. As of November 2017, software support was still pretty rough.