Before discovering PyDev, I rather used Vim and mc as my "development environment". And I rather disliked everything related to Java, because I often had trouble with it in the past.
PyDev(*)/Eclipse changed that. It gives me so much support while coding and debugging that my productivity is substantially better now. It often even finds errors in the code.
Installation was easy (I used the download version of eclipse, not a package of my Linux distribution).
Although it might be a problem on old machines, it works great on my development machine (Notebook with 1.1GHz Pentium M, 1GB RAM, 1280x800).
(*) I also use PyDev Extensions.