I have been messing around with Node.js pretty much like I did with Ruby back in the day.
Almost no function in Node directly performs I/O, so the process never blocks. Because nothing blocks, less-than-expert programmers are able to develop fast systems.
This statement is enticing, encouraging, and completely fucking wrong.
via Node.js is Cancer.
Next, suppose you're an expert programmer, and you've got some CPU bound work that you fork off to child processes to keep your event loop trucking. OK man, how complicated do you want to make this thing? At full capacity, you're at par with threads, provided it's not memory bound. At this point, you are less focused on solving the problem at hand than you are on coming up with something you can blog about and get on programming Reddit.