The castle structure and how the Hagrid trains ride through it are amazing. IMO the AA's aren't the best done, but it also doesn't take away from the attraction. It's a fantastic ride! With that said. Unique? Not sure. Just rode Chetah Hunt in Busch Gardens. This is more of a comparable ride, than CR is. I couldn't tell you which ride is better. Same Thing with the JP Coaster. There are comparable coaster experiences out there.
Cosmic Rewind is a unique amazing experience only at Epcot. Hagrids and the Jurrassic Coaster are amazing, but unique??? Not so sure.
Not to mention CR could be more approachable for families. Personally I think CR is more comparable to "The Forbidden Journey, just on a coaster track.
I think CR will give Hagrids a run for its money in regards to popularity.