Lo-Dash v.s. Underscore

A breakdown of the advantages of Lo-Dash over Underscore:
http://kitcambridge.be/blog/say-hello-to-lo-dash/

The creator of Lo-Dash explain why it is a superior choice to Underscore:
http://stackoverflow.com/questions/13789618/differences-between-lodash-and-underscore

Lo-Dash v.s. Underscore benchmarks: http://jsperf.com/lodash-underscore

One may wonder that, since Lo-Dash is intended to be a superset compatible to Underscore from the beginning of design, why not contribute to Underscore directly, e.g. by merging the new features back into Underscore, instead of developing a new library? This thread in GitHub may serve as an answer to the question.