Hi, I'm the creator of LokiJS. Just dropping in to say that 1.1 will be released really soon, among other things we're gradually implementing mongodb api compatibility for simplicity of use for mongo users. However, DynamicView will remain the method of choice for fast access. Among other things we introduced there's prototoype deserialization (load your JSON into proper "class" instances), a Changes API that keeps track of changes for remote sync-ing, added indexeddb persistence (as well as the already present fs for node and cordova) and you can even write your own persistence plugins for as long as it supports a couple of methods.
It is also interesting to note that LokiJS has gained a bit of popularity as a native replacement for redis (there's even an express loki store plugin on github), and yes, find operations on an indexed field on an average machine are still upwards of 500k/s
Loki already runs as a server but in q1/q2 of 2015 we'll also add standalone capabilities with tcp and http wrappers.
That said, I like ForerunnerDB too