Butterick's is a wonderful resource despite the site itself being a little bit of a UI/UX pain (the invisible left/right page turn zones always get me), and as long as you ignore a few of his strange quirks (like the mentioned penchant for SMALLCAPS LINKS).
Applying his basic rules on line length, font choice, point size, and line spacing can massively improve any document. And it's one of the only serious resources for people whose "real job" isn't typesetting: most stuff online is for design pros who use InDesign or similar, not Microsoft Word (or html/css) like the rest of us.
Butterick's advice on tables is great: delete ALL the borders, then slowly add back only the ones you need.
Disagree on one point re: TFA - Butterick's version of the scientific paper is much improved, largely because of the narrower margins. It just looks bad on the page because the image is small. Print both on 8.5x11" paper and the Butterick version would be much better.
