Mocha

Javascript unit tester and runner
Built for testing NodeJS modules
Can be configured to BDD (jasmine style) or TDD (qUnit style)

vs Jasmine

Mocha has better BDD style
Mocha is better at testing async
Mocha has no spies built in. Most use sinon.js for this.
Mocha has no assertion framework. Most use chai
Jasmine is more of a complete all-in-one solution. Mocha goes for basic functionality and extensibility via plugins