I heard about a similar method before. Using Excel tables seems to be quite common. I am writing two paragraphs in Endnote - one is a little summary including question, method and result, the other is a personal assessment of the article and its relevance. I then copy these writings into one or two Word documents, which then, with some editing work and extra writing, become subject overviews.
I am just a few months into my PhD, so I will see how this method works ;)