I was an ACORN canvasser and later an ACORN organizer in both Atlanta, GA and Brooklyn NY, in the early 1980s I was a pretty good canvasser (fundraiser) but for a variety of reasons a terrible organizer (bad period of my life, put into to field among some of the usual ACORN flakiness). Despite my experiences as an organizer it taught me an enormous amount about how to organize effective campaigns, and I was able to use that experience and knowledge later.
ACORN is probably one of the most effective progressive organizing efforts in recent history at its best. There is a reason the Right targeted and destroyed ACORN. It was doing a bangup job at voter registration, and was an in-your-face movement in the tradition of Saul Alinsky.
It also attempted cutting edge union organizing, attempting to organize workers that the labor movement was refusing to acknowledge at a time when low wage service industries were becoming a much larger part of the labor force.
I have quite a few criticisms of ACORN's approach based on my own experiences, but a lot of admiration and praise also. I think we need to be honestly analyzing what ACORN did, why the Right was able to destroy it so utterly, and how to learn the lessons of ACORN in a way that helps up move the progressive movement forward in those areas in which ACORN excelled.