I bought version 1.0 when it was released this week and since then I have stopped using TextMate (or occasionally NetBeans) for Rails development. The things that won me over: very fast interface, auto-complete, command-B to jump to method declarations, command-F12 for a popup mehtod list for the current file, pretty much full refactoring support, jumping between view and controller action code, etc. I still think that TextMate is much better for browsing large projects, but if you are coding, I think that RubyMine is much more productive.