Ever since I read these two posts, I've been trying to find ways to concretely prove him wrong. The farthest I got was with Performance, where you may have good reasons to improve performance at the expense of harming maintainability. But in good code, this is done only if the improved performance are part of the requirement. In this case, you've got to measure the code compared to some other alternative that still meets the requirement - leaving you once again to measure maintainability only.
My tiny addition to Oren's statement would be - as long as the requirements are fulfilled.