Seemingly opposed to most of the posts on the new design, I must say that I really like the design; it matches Windows 11 design philosophy and is better integrated visually than even edge.
It seems the interface is very efficient, as it runs much faster than any other browser on my system, even with my basic set of plugins installed and running.
The design also reminds me of the obsidian.md interface, which I like a lot.
What I find to be true, is that customizability for now is mostly nonexistent. I expect, though, that it will be (re)added in the future.
The tab islands are great; it would be nice to be able to close a complete island with one click.