Living in an apartment with difficult walls, I wanted a guitar hanger with a large backplate. This is about the biggest I've found. It's plastic, but it's very tough plastic, and the rotating grip works well, although it's probably too narrow for wider necks like 6 string basses, 8 string guitars etc.
Main drawbacks - the installation instructions are only in German, it doesn't come with any screws or wall plugs, and the back panel is moulded rather than flat, so you can't attach Dual Lock or similar to it and attach it easily to a flightcase for temporary use without screws.