I first tried it at the Breck brewpub in Denver and didn't want to leave as it was so good -nice balance of vanilla, sweet dark malt, and a bit of bite from the chocolate malt that prevented it from being cloying. Wife brought me a sixpack back last year after a trip to Denver and I happened to have my own version on tap at the same time and thought the their version was a little sweet with very little roasted flavor - just alot of vanilla - I am sure freshness may have a little do with the percieved change. It was still good though, just not as good as mine.
My girlfriend loves this beer, but I find the flavor inconsistent. The first time I tried it the vanilla was so subtle that if it wasn't called a "vanilla" porter I wouldn't know the difference. Another time it was so perfumy I almost gagged from the smell. Can't recommend it based on my experience.