The biggest changes since then are use the fast coder as the default in early 2018, then switch to the twoloop coder on 2021-05. There have not been major improvements to the native FFmpeg AAC encoder since the flurry of activity in 2015-2016, so FDK is still better. I guess the author did not perform a comprehensive personal listening test. The source was originally on the FFmpeg Codecs Documentation for the AAC encoder. The claim that the FFmpeg AAC encoder is better is incorrect. Is this true, and if so, what was the source for this information? However, this third-party tool is the only reference I can find to the claim that FFmpeg's default AAC encoder is now superior to FDK-AAC, and the relevant FFmpeg wiki page itself remains unchanged. So if you need that or want better quality at lower bitrates than 96kbps, Note: FFmpeg's aac encoder is no longer experimental and considered equal orīetter in quality from 96kbps and above.

However, recently attempting to build FFmpeg with the media-autobuild_suite showed the following when presented with the FDK-AAC build option: Build FDK-AAC library and binary? This is currently the second highest-quality AAC encoder available in FFmpeg and does not require an external library like the other AAC encoders described here. Requires ffmpeg to be configured with -enable-libfdk-aac (and additionally -enable-nonfree if you're also using -enable-gpl). This is currently the highest-quality AAC encoder available with ffmpeg.

I wrote this about a year ago while working through my own way trying to compile a FFmpeg for Windows, based on the premise in the FFmpeg wiki that:

Xmedia recode aac vs faac