This is news to me, so I'll look into it to see how it differs from ggplot2.
EDIT 2: It seems more like that the difference is that ggvis is more for interactive charts, but then it requires a dependency on Shiny, which is not optimal for blog posts.
Thanks for linking the paper! I'll definitely read over that. I've heard it mentioned before ...
I'm definitely not an R guru or "in" on the latest news, but it seems that Hadley Wickham (who probably single handedly is the reason R is still relevant) now works for the RStudio guys and he's reworking his tools. plyr is now dplyr and gpplot2 is now ggvis. And there also another tool called tinyr. My understanding is that they're still in development, but they'll ultimately provide an "integrated" ecosystem for processing data.frames (with hooks into the RStudio IDE)
I would recommend using theme_bw(), which helps solve some of the problem with the gray background.
EDIT: This is ggvis: http://blog.rstudio.org/2014/06/23/introducing-ggvis/
This is news to me, so I'll look into it to see how it differs from ggplot2.
EDIT 2: It seems more like that the difference is that ggvis is more for interactive charts, but then it requires a dependency on Shiny, which is not optimal for blog posts.