The editor which makes me most productive as a developer is the one I have to think about least. I spend an order of magnitude more time reading and thinking than typing, so no amount of increased editor efficiency could make a significant improvement to my productivity. Having to stop focusing on the problem at hand in order to remember how to operate some sophisticated editor feature, on the other hand, could be a significant distraction. I want to use the simplest, most straighforward editor capable of doing the job, and if I have to spend a few extra minutes here and there doing some repetitive code munging by hand, it is not a problem because I can continue doing the hard part of the job (thinking) while my fingers are busy typing.
After using an editor for dozens of hours a week over decades, I decided it was worth the effort to write one of my own. I've been living in it for close to a year and a half now, and while it has a couple of quirks that occasionally bug me, it's nothing serious, and I feel pretty happy with my decision so far.
