This thread is archaic by now, but I just found it today.... hmmm, now, actually. So, let me answer too, although I'm almost one year late.
My best article is probably The Asylum in USS 2001. It was the longest and it took me about 6 months to research.
But the one I'm most proud of is Tanya in the Book of Sacrifices (I guess), although I never received any feedback on it. I liked it especially because I think that was the best story I could spin, of how there is an overarching plan that encompasses everything that happens to Tanya and how you only understand it at the end of her story.
Also, it was the first time I used different points of view in the story-telling, with the scenes in the Vistani camp framing Tanya's story. I like this weaving of plots and scenes, and that's what I try most to do in my works, and that is perhaps why I like this that much.
Interestingly, the article I've had most feedback about (and that has been very little, unfortunately) was the Love-Torn Ghost in the same BoS. I've been told the ghost there had been well-made, but I don't fancy her as much as Tanya. I think there is a bit too sentimentalism there.
Well, that's it... but of course, my best, most fantastic, awesome (ahem) work to date is my online campaign blog....
Of course, all those adjectives are just a joke, but this has been my most time- and energy-consuming work dedicated to Ravenloft thus far.
Ail