Seaborn is now my goto plotting library for python. It's built on Matplotlib but with default themes and colour palettes that are much better out of the box and rarely require modification.
It plays nicely with pandas dataframes and has a number of useful built-in plots.
It is still a bit buggy, but I use it as well. Sometimes even only to get nice colours for Matplotlib (or more often: Pandas). Plus, there are many plots (e.g. heatmap, jointplot) that are practical and frequent, yet it would take a lot of lines of Matplotlib.