I’ve tried many, but the featurelessness of TextEdit is what I like about it. “Better” ends up being more distracting. I do like Sublime for actual dev tasks, though.
Sublime is my go-to for this. It can be customised to be much more comfortable to use, and projects let you have a set of files accessible with Cmd+P. I have different projects for each of my static sites. It's fantastic.