I am a quite happy user of Eclipse (I mostly develop in PHP and Python), however I found the answers to \"What specific productivity gains does Vim/Emacs provide over GUI text e
Some time ago I decided to learn vim beside Eclipse as well because of its powerful textual editing, search and navigation features. But - at the same time - I liked the project handling, code completion, refactoring and debugging features of Eclipse and I did not want to lose them.
Nowadays I use an Eclipse plugin called vrapper which provides me nearly all basic features of vim inside Eclipse without losing any Eclipse functionality. Of course it is not a full-featured vim but it gave me the productivity gain I 'expected' (motions, the dot operator, registers and marks). Also, this plugin can be considered the 'trial' version of vim where you can learn all basic and some advanced stuff within your 'best-known' environment.
There is another interesting approach called eclim. Eclim integrates Eclipse with vim from the vim side so you can use many features from Eclipse within vim.
For learning the basics of vim, this graphical cheatsheet helped me a lot.