Works and has keyboard shortcuts. You can customise the window layout and make a list of websites to automatically split screen from (google search is listed by default). I like that you can use ctrl + click. NiftySplit doesn't let me do that.

However, when you close the second window, the main window doesn't maximise automatically. So here NiftySplit wins.

Also note that the keyboard shortcut can't be rebound (not a problem for me, might be for some)

I don't think this extension is as bad as other users have commented. It works exactly as described, and I haven't encountered any bugs. One thing to note is that it won't work if you're testing it on the https://addons.mozilla.org website.

Exactly what I was looking for: Great, thank you!
Only criticism: It would be great if you could assign a function key to open the corresponding site in the next window when you click on a link. E.g. control-shift-click would be great.

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.

Not working unfortunately.

Doesn't work. It's a shame.

Doesn't work at the moment. Yes I have turned it on and yes the site I'm using is in the list of sites. It doesn't work with any site. Hope it gets fixed, it sounds great!

Edit: after updating still not working with any sites, not even google.