So I've used Backbone and now I'm using Angular. I work a lot with D3, creating SVG's in "render"-type functions (still grokking how this all fits in with Angular directives, but that's another story). One benefit from this article that jumps out is the smart rendering that React does.

If you had a scatterplot with thousands of points, being able to add or subtract a couple without re-calculating the whole thing would certainly interest me.