But there is something difference between the two. I found that "Widgets" is more favourable than "widgets".
Not to say that I can't learn something new, as it happens every single day.
However, I am not aware that the AdWords system distinguishes between upper and lower case in keywords at all. Ad text is an entirely different matter of course!
FromRocky, I wonder if the differences you see might depend on where and when you entered the case variations?
AWA