One of my pet peeves is people using the letter "u" to mean micro. Its a greek letter mu, "μ", and seeing as the entire thing is capitalised here, it could also be "Μ" (uppercase greek mu, not uppercase latin M)

The problem is that µ is usually hard to type (unless you have a Greek keyboard or a custom keyboard mapping). This said, although I tolerate stuff like "47 uF" in electronic schematics (also because legacy software didn't even allow the µ symbol), I definitely find horrible to see stuff like "us" instead of "µs" in an article.