I haven't tried Mongo.db, but Node.js takes up a lot of resources in a browser, Node.js apps feels a bit like the widest book strategy in the bookstore, you have to shove other stuff out of your browser, in order to use stuff that uses Node.js, and I feel that as a rather arrogant approach to deliver software, especially, when the functionality of Node.js apps doesn't really dictate the necessity.
AS for Javscript, there are worser languages out there, and the debuggers are good enough now, so it can be perceived as a "normal" language.
That may be so, but when I run something with Node.js in my browser, then I may have to close other things. So, wherever it runs, it really uses too much resources, and therefore I find it as a bad idea from the consumer perspective. It shouldn't be so, that somebody else, should dictate the content of your browser.
Node.js is something that runs on server ONLY. It's 100% like PHP but with JS instead. Your browser never sees nor executes Node.js code. It only operates on text a Node.js server produces.
The short definition would be: "node.js is something that eats up my browsers latency", something along those lines, and as far as I am concerned, that is everything I have to know about it. Node.js is a no stop for me.
AS for Javscript, there are worser languages out there, and the debuggers are good enough now, so it can be perceived as a "normal" language.