The Sickle is basically a SPAD version of the Gremlin... (the Gremlin pre-dates the Sickle, and I'd have to check, but I think the Sickle designer was trying to make a SPAD Gremlin.

As for anyone else flying them, for a while there were several clubs in Mass and CT flying them. I don't know if they still are, I've lost track of what's going on in that neck of the woods. Maybe someone from up there can fill in an update.