Hahaha, I just asked this very same question in a more ranty style, and a little less technical ([URL="http://monarchforums.com/showthread.php?t=3525"]http://monarchforums.com/showthread.php?t=3525[/URL]). I don't understand why people haven't talked about it more.
I just started messing around with it yesterday for a little bit, and it seems to work pretty well so far. The programmer's guide has some great examples that have error checking and other tips to get you started.
The COM I have used before, however, I have not used QAS in a program, and I was wondering if the effort was worth the work.
If you are not familiar with QAS, it is an address correction/scrubing tool. I work at a medical collection company, on a typical day 5k to 10k accounts pass before me and my colleagues. We export our addresses to be cleaning using QAS, but QAS offers an API to provide this via programming.