This one is simple.
In my not so humble opinion GURPS is never the wrong choice but its not always the right choice.
Its very good at any game that demands verisimilitude or some grades of cinematic play but its not great for supers or for relationship driven story games. It can do either of those to some degree but often not as well as a dedicated game would.
The Return of Planescape? - Curious. There is a brief note on this 'countdown' at Enworld.
15 hours ago