I’ve tried it and share my few thoughts:
First of all, the first time I’ve tried Smithay-based compositor and it is usable and even supports nvidia. It is a good thing just by itself.
The whole DE is better than I assumed. It in not much polished, but it is good as an experimental thing. I’ve noticed few developer’s creative attempts as “compacted” menubars and dialog pop-ups. I doubt they are good but reveal author’s intent to try create something new.
What I like: The application menu is nice, it also is quite modern: uses Wayland, CSD, Rust and implements modern UX.
What I not so like: UX has some weak parts: unnecessarily duplicated elements between the dock and the top panel. Icon style and preferences is not that good also. I really would like to see icon consistency across the DE which would not harm third-party apps. I also think the project need a designer in the team.
For now there are only few “native” apps. And I would prefer COSMIC will embrace existing GNU/Linux ecosystem and apps without trying to rewrite everything and creating yet another segregated platform as GNOME and KDE do.
Probably we don’t need new Thinkpads. And the old either. The main motivation behind the desire of people to by old Thinkpads is a desire to be a part of the club and culture, to look like a hacker, a geek. The same motivation had early apple fanboys. I hope smarter people will become less dependent from such crowdthinking phenomena not more.