Voted. I can pretty much say it was due to that thread.
My initial plan was to get the DA21, although the reason for that was mostly because it was the 3 DA pancakes that were on my radar at first since they were the reason I moved to Pentax in the first place, and I wasn't yet fully aware of the DA15 and the other Limiteds at that time.
The DA15 is now my most used lens, and I consider it to be one of the best and definitely one of the
most fun lenses I have ever used. (Previously used Nikon for half a decade, used some Canon and some m43rds as well).
For my style of shooting, wide angle is almost always where I'm guaranteed to have fun - but the DA15 just kicks it up a notch because of its size.
I know for some people, size and weight don't matter, but for someone like me who shoots a lot in crowded urban environments, the size of the DA15 just makes it a pleasure to use. Try weaving in and out of crowded streets and sidewalks with a large lens - it ain't fun.