A lot of comments in this thread are negative. As a developer using GTK4 and libadwaita, and as a user that uses gnome, I really like the changes. GTK4 brings some much needed changes, and the major bugs like listview scrolling being broken or bad text rendering on non-hidpi displays suck, but both have people working on fixing them. Libadwaita is a huge improvement, and makes it way easier to build good apps.
As for themes, I quite like the new libadwaita theme, and prefer it to the default GTK theme. You're free to disagree, but you can't say your opinion is correct, nor can I.
Keep in mind that libadwaita is an optional library _specifically for gnome apps_. If you don't like gnome, don't use libadwaita. If you want the widgets from libadwaita, but don't like the styling, then either copy the code (it's open source, fork it!), or use libadwaita and disable the libadwaita stylesheet (and add styling for the widgets that aren't part of GTK).
As for themes, I quite like the new libadwaita theme, and prefer it to the default GTK theme. You're free to disagree, but you can't say your opinion is correct, nor can I.
Keep in mind that libadwaita is an optional library _specifically for gnome apps_. If you don't like gnome, don't use libadwaita. If you want the widgets from libadwaita, but don't like the styling, then either copy the code (it's open source, fork it!), or use libadwaita and disable the libadwaita stylesheet (and add styling for the widgets that aren't part of GTK).