The only thing that bugs me with this addon is that it seems to select the tab to the right of closing tab for a split second before switching to my preferred tab. This is only really noticeable when either using a tab suspender addon or having firefox set to not load all tabs on startup.
Other than that it does exactly what it promises to do. Simple and functional.
Edit: My complaint above is a restriction in firefox as per the devs response. This changes my review to 5/5 as it is in all other aspects perfect. Good job!