I am a relatively new user (< 1 year) of IDEA and have used IDEA-7 and IDEA-8.1. So far the experience has been fantastic. Wild horses couldn't drag me back to Eclipse. From what I've read about Maia (IDEA-9) so far, I haven't seen any compelling reason to upgrade from a Java or Groovy/Grails point of view.
Am I wrong about this? If yes, what are the huge, new productivity benefits that are worthwhile for me to upgrade to IDEA-9? Note that my main platform is agile Java (Java 6, Spring, Hibernate/JPA, web-services, ActiveMQ, etc.). I also use Groovy/Grails from time to time. It's unlikely that I'll be using JEE 6. I use Ubuntu 9.04 exclusively - both at work and home.
Thanks very much.