Have been using OneTab for years. Great extension, would love to rate it more highly, unfortunately there's too many usability issues. 1) I've just imported saved urls and because no feedback is given, I ended up importing the same URLs several times, and losing the latest open pages. No way to undo that, the "reject duplicates" is not active by default, and does not work retroactively.
2) I've submitted a request a long time ago, to select a group of tabs easily, and restore them all - not necessarily the whole group. Bulk delete should also be an option. Unfortunately, available options are very limited, and the extension has remained unchanged for a long time. Still grateful to the dev for creating something that should be native to any browser, but it really needs more work for me to give it more than 3 stars.