Well I'm biased since it's our product but I think JackDB[1] is both nice and efficient. It runs entirely in your browser so it's naturally cross platform. [1]

Well I'm biased since it's our product but I think JackDB[1] is both nice and efficient. It runs entirely in your browser so it's naturally cross platform. [1]: http://www.jackdb.com/ http://www.jackdb.com/