At first I couldn't get it to do anything - right click then "Open link in next window" didn't open a new window, or open a link. However, after about 10 minutes of trying (and maybe restarting Firefox) it started working. It's great when it works. The only major bug I have found is that the scaling of the windows is wrong when a new window is created first time. I use Windows Snap (window tiling) to correct for this which is a minor hassle.

It works. In my opinion, better than NiftySplit.

But it overwrites the basic standard shortcuts - Ctrl+Click and Shift+Click. This is not good. It should have its own shortcuts or an option to disable them and leave only the items in the context menu.

There is also an option to enable/disable the extension by clicking on its icon - this doesn't seem to work for me.