I haven’t used a different browser in a good while, so I’m not sure that these issues don’t exist elsewhere, but here’s a few:
For a very long time after the rework, reordering tabs was not possible. Only recently was this added again. But there seems to be no acceleration, so moving an old tab to the front takes forever. Even worse, this feature is still not available for private tabs (since you can’t select those at all).
Quite often when I switch to the tab overview, it doesn’t automatically scroll to my current tab so I need to do that manually.
I’m also not a fan of the “jump back in” view that shows up every so often instead of the content of my tab. Why they would assume I’m interested in anything besides what I intentionally opened is beyond me.
Creating a new tab is more cumbersome than it needs to be. I think you were able to do that by scrolling to the right on the address bar of the rightmost tab. A dedicated button would be even better.
I think it’s a great browser, and pretty much the only one I use, but in my experience everything does not work perfectly.