Anyone used it / programs using it? In theory, it looks like its a reasonable basic aff system, but real world experience is always better than reading the authors own blurb...

Not used that one, but we've used another of their scripts.  It was very "un-drupal" but actually pretty good.

Well, that's comforting, at least. The dev seems to be a fairly responsive type, actually engages with customers etc

We found the same with the dev.  I'd happily use his stuf again.