RTVS builds on Visual Studio, which means you get numerous features for free: from using multiple languages to word-class Editing and Debugging to over 7,000 extensions for every need:
A polyglot IDE – VS supports R, Python, C++, C#, Node.js, SQL, etc. projects simultaneously.
Editor – complete editing experience for R scripts and functions, including detachable/tabbed windows, syntax highlighting, and much more.
IntelliSense – (aka auto-completion) available in both the editor and the Interactive R window.
R Interactive Window – work with the R console directly from within Visual Studio.
History window – view, search, select previous commands and send to the Interactive window.
Variable Explorer – drill into your R data structures and examine their values.
Plotting – see all of your R plots in a Visual Studio tool window.
Debugging – breakpoints, stepping, watch windows, call stacks and more.
R Markdown – R Markdown/knitr support with export to Word and HTML.
Git – source code control via Git and GitHub.
Extensions – over 7,000 Extensions covering a wide spectrum from Data to Languages to Productivity.
Help – use ? and ?? to view R documentation within Visual Studio.
I’ve been using it for a little while and it’s pretty snazzy for integrating with SQL Server R Services. R Studio is still more feature-rich, but RTVS is definitely catching up.