So far I've stuck with Eclipse, I used Java / C++ tooling previously so RDT just slotted in, and I'm pretty impressed with it. I know it has a reputation as slow and buggy, but I've found neither to be the case - Admittedly I've had bad builds of Eclipse in the past but I've stuck with 3.1.0 and it stays up 24/7 (literally).
That said, I use vim a lot too for single scripts, my 'tryout' stuff, and configs etc. I have four virtual desktops, with Eclipse, Vim, bash and Opera. Eclipse kind of handles 'the project', but I'll often walk around after running rake for example to do some small updates with vim and then refresh into Eclipse.
The main pluses of RDT for me are:
* The Ruby outline is *very* useful.
* Test::Unit integration works nicely (as far as I've pushed it up to now, at least).
* Sits nicely with JDT and CDT, I can have the three perspectives open at once if necessary.
Very handy today when I've been getting a handle on the libxml/libxslt binding project.
* CVS support is a boon. I used to do everything from the command-line, honestly I did. But
there's just so much less to remember, and it's nice to be able to browse repositories,
get diffs, run compares and everything all in one place. Sorry... 
* Eclipse's secret weapon - local history. I don't use this as much as I should, but it's
still saved my life more than once.
* Software update features that work, and even keep everything version consistent, most of
the time.
Also, the debugger seems to work okay, though I've not used it outside of playing with it. Generally, I hate debuggers, and integrated debuggers are even worse 
A few cons I can think of:
* RI view doesn't work, though I suspect that's down to faulty or incomplete Ruby 1.8.3
packages on Fedora, because it doesn't work properly from the command-line either
(it's missing a lot of docs).
* It has once or twice lost control of Ruby processes started with Run. Again though,
I tend to do this from a shell anyway.
I have to temper this by saying that I've not seriously tried the others (better the devil you know and all that), but then I've not found any reason to thus far.
Ross
(Platform: x86-linux)
···
On Wed, 07 Dec 2005 21:13:11 -0000, Curt Hibbs <curt.hibbs@gmail.com> wrote:
There's been a couple really good threads that are still ongoing about Ruby
IDEs in general and ArachnoRuby, Komodo, and Eclipse/RDT in particular. I've
been following these threads very closely because I'm writing an article for
O'Reilly on Ruby IDEs, and so far these threads have been really helping me
collect information for this article.
So, What I'd like to do is to consolidate everyone's opinion in a single
thread both for my benefit, and your's, too.
--
Ross Bamford - rosco@roscopeco.remove.co.uk
"\e[1;31mL"