We have some really strict rules about IDEs and stuff: it's gotta all work in an automated build. After that, do whatever makes you the most productive.

Thus, we have some developers working in the MS Visual Studio IDE. And some using vi. And some using nedit, emacs, fte, etc. I even know one guy doing perl using EPIC (Eclipse). I do try to discourage using notepad/wordpad and Word, however. ;-)

Editor choices are the least of your worries. Productivity is one of your greatest worries. If this new guy wants to use a professional toolkit that costs a mere $800, my vote is to say "let him." Personally, I use free environments, but that's because they work for me. And I've managed to put in more than a couple tweaks to help it work the way I work. That obviously doesn't work for everyone.

Focus on the things that really matter: the code works correctly, quickly (as in development time), and the code itself is maintainable. How you get it there is not really a concern. If you can whistle the code into a modem faster than using vi, then go ahead. Personally, I have trouble getting the ( and backspace characters right that way.