Upgrading to any new operating system can be problematic. However, if you depend on R and R Studio for your living, I would highly recommend NOT upgrading to OS X Mavericks, despite its nonexistent price tag. Personally, I have seen painfully sluggish UI behavior with R Studio 0.97.551 since I updated to the latest version of Mavericks (I have also seen such behavior with Google Chrome, previously the fastest browser by far on my Mac Book Air). Confirming my suspicions was the following helpful blog which I recommend reading: http://blog.rstudio.org/2013/10/22/rstudio-and-os-x-10-9-mavericks/

AuthorSean Murphy