Basement Delving: Invincible Mayfair

Ever since I developed an active interest in role-playing again a few years ago, I've been fascinated by the old Judges Guild "City State of the Invincible Overlord" stuff. I even bought quite a few PDFs, with mixed results. But I had forgotten all about these things:

Can someone with real Wilderlands clue say something about these products and how the compare to the "official" Judges Guild version? Is this stuff just "inspired by" the Wilderlands or is it an "updated take" on the setting? Is the stuff compatible, for example regarding cultures and locations described? I know that there was some kind of weird lawsuit between TSR and Mayfair over this, anyone have details about that? And finally: Should I hold on to this stuff or get rid of it? The production values seem pretty high, but if it has nothing to do with the "real" Wilderlands then I doubt it'll hold permanent interest for me.