Speaking for me, I find the notebook ideal for making things that I want to present or show others. I think that it's not so great for:
* playing with data by running a lot of different commands.
* writing a complete python module or method.
* editing my code down to a single, useful nugget.
Rodeo and Spyder (and RStudio) basically give you a terminal, a bunch of scratch paper, and a look up guide for objects that you've instantiated and graphs that you've drawn. If you haven't ever been tempted to open up an ipython session and a text editor, you probably don't need this. If you have, then this might be worth a whirl.
I completely agree. I feel bad self-promoting here, but there is a middle way. At Sense (https://sense.io) we've combined real editor with a notebook like console log. RStudio and Rodeo, by comparison, are basically copying traditional IDEs without a comprehensive log that includes visualizations. This makes it much harder to share results.
On Sense, your scripts are just scripts (comments are markdown formatted), but when executed in a Sense engine the REPL produces a rich console log similar to a IPython Notebook. This makes the logs great for sharing, without sacrificing the ability to refactor code into libraries, run it locally, or use code-oriented version control tools.
So you're basically offering an R studio that generates a series iPython notebook-esque plots/visuals rather than displaying them one by one in the "Plot" Rstudio window? Is that a fair characterization?