Having been on both ends of the pen, I find plain English documents best for support and user help purposes. Any doc that is simple enough for users to comprehend leaves me with more time to do more useful work. The same is true of technical documents. While writing in a very technical, rigid style might give people the impression that you are a genius, in the end, if your fellow developers or system support team members cannot clearly understand it, then you have failed and the document will gather dust or be used to fuel the furnace. Better to put effort into clear system designs and well documented code.