React.JS and what server to use?

I have used Ember.JS a good deal over the past year as well as a little
Angular. I found Ember to have some cool concepts and I liked writing
mixins in Ember, but something about Ember seems very complex to me and
have felt like I wanted something simpler to work with. I have felt that
Rails has been slipping a bit and the popularity of Rails has not been
growing as fast as I had once hoped for. Because of that I have had to
focus more on JavaScript and JS frameworks.

I watched a video of Jing Chen on the Facebook team explain problems
MVC complexity. I felt like what she was saying made alot of sense and I
have heard that React.JS can do alot for a simple library.

I found this post which explains different ways of using React.JS with
Rails and Flex. (Flex is the MC in MVC and React is the V), however they
all seem to have pros and cons and it is not clear what is the best
approach. The third approach seems to be to use two servers, Rails and
Node. That does not seem optimal at all.

It seems like to use Flex you need to use Node, so it appears if I want
learn more about Flex then I have to possibly focus more on Node as a
server …