I’ve recorded my experiences with Amazon Basics, Ergotron LX and Herman Miller Ollin arms on the owner‘s thread - for my criteria, Ollin winds hands down. All the other ones were WAY too stiff to move around/adjust.
My experience with Ollin:
https://forums.macrumors.com/threads/apple-studio-display-owners-thread.2337972/post-32435105
Amazon Basics:
https://forums.macrumors.com/threads/apple-studio-display-owners-thread.2337972/post-32375664
Ergotron:
https://forums.macrumors.com/threads/apple-studio-display-owners-thread.2337972/post-32398013
My experience with Ollin:
https://forums.macrumors.com/threads/apple-studio-display-owners-thread.2337972/post-32435105
Amazon Basics:
https://forums.macrumors.com/threads/apple-studio-display-owners-thread.2337972/post-32375664
Ergotron:
https://forums.macrumors.com/threads/apple-studio-display-owners-thread.2337972/post-32398013