tl;dr:

I'm new to Seaborn and matplotlib in general, but Seaborn is a wrapper on top of matplotlib, and from what I can tell, was borne partly out of frustration with how hard it is to get matplotlib graphics to look decent out-of-the-box. Which makes it, in one sense, kind of like what ggplot2 was to R's standard plotting tools.

However, Seaborn has a more object-oriented API, among other things:

http://stanford.edu/~mwaskom/software/seaborn/introduction.h...

> Seaborn’s goals are similar to those of R’s ggplot, but it takes a different approach with an imperative and object-oriented style that tries to make it straightforward to construct sophisticated plots. If matplotlib “tries to make easy things easy and hard things possible”, seaborn aims to make a well-defined set of hard things easy too.

There already is an attempt to port ggplot over to Python, and its authors' opinion is that its API should look like R's ggplot2, which means the syntax is not Pythonic: http://ggplot.yhathq.com/