I personally do not use Integrated Development environments (IDEs) for R, or for that matter for any programming language. From my point of view, they take up too much precious real estate on the screen, and most important, they generally do not allow me to use my own text editor and my own abbreviations and macros. Since I want to have a uniform editing environment no matter whether I am programming, typing e-mail or whatever, IDEs are not for me. I just use Vim, with my own abbreviation collection.
So for example, I’ve never used RStudio (gasp!). I know many people who swear by it (and maybe a few who swear at it 🙂 ), but it’s just not for me. ESS (Emacs Speaks Statistics) is great for the hard core R people, and in fact I occasionally use it — I have an Emacs tutorial, by the way — but not too much.
If you do want to use an IDE for R, and want something different, I’ve always admired (from afar) StatET, for which there is a nice introduction in progress. It does take some configuration, and Eclipse requires some learning (I have a tutorial for it too), but StatET has always impressed me as very well-designed.
Disclaimer: I do not know whether the StatET article’s claims about RStudio are correct. My point is that the article is a nice introduction to StatET.