Agree completely about zero build time!

I've been using IntelliJ IDEA for Java development for the last 4 years, and before that I used C and C++ using Emacs for 7 years.

I am way more productive in IntelliJ IDEA than I was before. One reason is the instant feedback on syntax errors when I type the code. I don't need to compile to see them, as I used to in C and C++. Another reason is the navigation support you get in an IDE.

I've written more about the differences in development environment here: http://henrikwarne.com/2012/06/17/programmer-productivity-em...