It has been very heartening to see the improvement in students' writing in the course of a single quarter-often going from barely comprehensible to excellent technical presentations. I believe that the writing improvement has also been visible in other courses, as many courses require final project reports. Certainly the reports I have seen in the VLSI Design Project course have been much better than the corresponding reports that I got at Cornell.
I have had engineering students tell me after they graduated that the technical writing course was the most useful single course they took. Although they have dozens of classes with math, science, engineering theory, and design practice, this is the often only class in which they pay close attention to writing and speaking skills.