I'm a
technical writer, and here's my perspective.
It is a thankless job. Your name is not included in the end work. The engineers change the specifications and neglect to inform you. There are a minimum of two design spec changes that come to light only after you have sent your manual off to the printer. Kurt Vonnegut, Jr., was correct in stating that Tech Writers must avoid interjecting their opinions or thoughts into their writing. Most tech manuals are bland, boring factual papers.
Why do I write technical manuals? I enjoy it very much. It takes skill to take a product and teach someone how to use it or repair it. I don't write software manuals personally, since I am a hardware specialist. My tech manual writing jobs included training courses for classrooms, component-level repair of hardware, module replacement, and how to use the device. The end audience must be considered in writing technical manuals. Users are the least technical people in general, where component-level repair techs are the most familiar with the inner details of a device.
One outlet for prose is Everything2. I get to voice my ideas and opinions in my writing, so I "get it out of my system" before going back to tech writing.