OpenWRT is very good, but the installation and upgrades are not easy. There is a zoo of images for different hardware, installation options and tools. It has to run on small devices, so there are limitations. The documentation on Wiki is scattered and could be improved.
I had to search forums for weeks for a custom package installation for my router. Right now I have been trying to upgrade to the latest version via LUCI for a while, and it stucks. Probably have to wait for few weeks, go through CLI and maybe search forums again.
I just thought I am paying a hefty time price for a bit more expensive x86 mini pc and AP.