Research Advisor is an excellent writer and editor. She hasn't had many opportunities to edit student work and has said that it has been a learning process to figure out the best ways to help Awesome Technician (who is not a student but is a student-like young scientist) and I with our papers. I've noticed that she seems just a little uncomfortable giving me feedback on my writing as though she seems slightly afraid that I might get defensive. So far her comments have been nothing but constructive, really improving the paper, so there have been no problems. AT concurs.
Awesome Technician and I both minored in English in college and we credit the "workshopping" that was the centerpiece of many of our English courses with thickening our skins -- a good trait for budding scientists. My university required all students to take a junior-level writing course. My minor was essentially comprised of several of these courses (plus creative writing, linguistics, and an independent study writing my science department's alumni newsletter). I had business writing, exposition, and technical writing, each designed for juniors in other disciplines to improve their written communication skills by forcing them to write more. I didn't really get a whole lot out of these classes since they didn't progress -- each one was independent rather than working together in a sequence to build skills. After the first one it was pretty easy for me to bust out an A paper, whereas my classmates who were, say, engineering majors who never had to write more than a paragraph struggled. Thus I wasn't challenged to improve my skills, but I did gain from the practice.
There was one aspect of these classes that taught me some skills I didn't happen to learn anywhere else, however. They all had a workshopping component, where students read each other's work and discussed it as a group. It's one thing to receive the critiques of your friends and classmates, but it's really different to give it. Being on the other end (which is pretty rare at the undergrad level) teaches you lots of technical things about writing because the mistakes of others stick out at you in a way that your own flaws don't. It also gives you empathy for the person reviewing your writing because you know where they are coming from when they make certain types of comments. Most important for me now, it helps you take criticism in the way it was intended -- you have the experience to realize that the criticism isn't about you.
I'm very grateful to have an advisor who is sensitive to my ego. She can really shred a paper without being mean or even judgemental. In fact, I almost wish she were a little more to the point at times because I think it would make things go faster. I could take it.