I think it would be useful if a Favorite could store two paths, one for the left and one for the right lister. (I remember someone mentioned tab groups as a workaround, but it's not very convenient.)
You could make a button or bunch of buttons which each open a pair of paths using the Go command. (You can open two paths in one line although I can't remember the arguments off the top of my head.)
The interface for editing the buttons wouldn't be as nice as the one for favourites but the end result would be the same.
Yeah, I have created one button like that - it's kind of tedious though, which is why I hope the author implements something easier 
Ok, so then how about saving Layouts with the 2 paths opened in their respective file displays? Open the paths you want in your left and right file displays... Settings->Lister Layouts->Dave This Lister... done. Maybe that will be a little 'less' tedious for you than always making new buttons with Go statements...
Or, better yet make 'saving' the layout even a bit faster with less clicking by binding a hotkey or creating a single button to run the command: Prefs LAYOUTSAVE=single LAYOUTNAME. It's NOT favorites, but it should get the job done 'quick and easily'...
You've been watching too much Red Dwarf.
That's a pretty good idea steje - especially since I don't use Layouts for anything right now. And yes, both solutions are pretty easy, just not as easy as I want them to be. I'm really lazy.
LOL - doesn't everyone Dave their listers?
I'm daveing mine right now!
Dave? Dave's not here...