Having been working inside an IDE for a while now, I felt very unproductive, when I recently made the switch to Ruby development for a living. In the past 6 months or so, I have tried every Ruby IDE out there and I found all of them to be lacking in quality. I was quite frustrated especially when editing rhtml files and the IDE would crawl to a halt and in some cases even run out of memory. I attributed this to the new-ness of Ruby support in these IDEs and the difficulty in parsing a dynamic language like Ruby. But over the past month I have been quite happy with Netbeans Beta 1 as it has become quite usable compared to the other IDEs.

Also, the support for fast-debugging is great. I used to wait for hours (literally) to hit a break-point with the old ruby debugger. But with the Fast debugging, I can use debug mode without it being un-usable.

I joined a project that already had a substatial amount of Ruby on Rails code written using just TextMate and vi. So, I was hoping that it would be possible to migrate that code into Netbeans and I was pleasantly suprised to find that it all just worked when I used the exisitng project option in Netbeans. I was then able to start debugging the project and even set break points inside rhtml files which I could not do with other IDEs. Since my project requires a specific version of Rails (definitely not the latest) I was worried it would not let me use my own version of Ruby and Rails and again I was pleasantly surprised. I found a few videos and demos along the way that made life easier as well :

Editing Ruby in Netbeans
Code completion in Netbeans Ruby Editor

So try out Netbeans 6 if you are doing Ruby development and are looking for a decent IDE.