I always find myself doing a bit of both. I hate editing in the first place, but when I go back and give it a once-over for pacing and mechanics and what not, I find myself occasionally adding or subtracting just a sentence here and there. I've never really overhauled complete posts, or chapters, or what have you. If it's not working, it gets scrapped entirely and I'll start from scratch until I feel like I've gotten it right.

Also, screw excessive setting and description. Trust your reader's imagination.