There's scant few articles on going from Python to R...and I think that has given me a lot of reason to hesitate. One of the big assets of R is Hadley Wickham...the amount and variety of work he has contributed is prodigious (not just ggplot2, but everything from data cleaning, web scraping, dev tools, time-handling a la moment.js, and books). But that's not just evidence of how generous and talented Wickham is, but how relatively little dev support there is in R. If something breaks in ggplot2 -- or any of the many libraries he's involved in, he's often the one to respond to the ticket. He's only one person. There are many talented developers in R but it's not quite a deep open-source ecosystem and community yet.
Also word-of-warning: ggplot2 (as of 2014[1]) is in maintenance mode and Wickham is focused on ggvis, which will be a web visualization library. I don't know if there has been much talk about non-Hadley-Wickham people taking over ggplot2 and expanding it...it seems more that people are content to follow him into ggvis, even though a static viz library is still very valuable.
[1] https://groups.google.com/forum/#!topic/ggplot2/SSxt8B8QLfo/...