Writing on Spec: Yay or Nay?

Recently I got an email in response to one of my queries saying, "I'd love to take a look at this article on spec. Thanks." Not exactly a rejection but not what every writer dreams of hearing either. Despite the fact that most professional writers would scoff at writing on spec, I'm tempted to do it.Here's why: if the editor was completely disinterested in the topic then she wouldn't have asked to read the article. If I can gather enough information 0n what style guide they use and the preferred word count, there's no reason I couldn't write up the article over the next few weeks (the topic is familiar to me and doesn't require much research) and wow the editor, potentially leading to other (non-speculative) assignments. Worst case scenario she doesn't like the article and I sell it elsewhere.For those who are perhaps unfamiliar with this concept, here are a few other posts to get you up to speed on the topic:Golden Pencil: Writing On SpecInkthinker: Did I Misunderstand What a Query Letter Is?Quinn Creative: Should You Write On Spec?
What do you think?