What Ruby IDE do you prefer?
I've been using Eclipse with RDT (not RadRails) a lot lately, and I'm quite happy with it, but I'm wondering if you guys know any decent alternatives. I know NetBeans also supports Ruby these days, but I'm not sure what it has to offer over Eclipse.

Please, list any features you think are brilliant or useful when suggesting an IDE, makes it easier to compare.

Also, I said Ruby, not Rails. While Rails support is a plus, I prefer things to be none Rails-centric.
What Ruby IDE do you prefer?
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I've been using Eclipse with RDT (not RadRails) a lot lately, and I'm quite happy with it, but I'm wondering if you guys know any decent alternatives. I know NetBeans also supports Ruby these days, but I'm not sure what it has to offer over Eclipse.

Please, list any features you think are brilliant or useful when suggesting an IDE, makes it easier to compare.

Also, I said Ruby, not Rails. While Rails support is a plus, I prefer things to be none Rails-centric.