I presented a talk at CUP 2010 in Santa Fe on KNIME, Pipeline Pilot and visual programming languages in general, with comparison to other visual programming languages and text-based toolkit approaches. I've broken the talk up into parts, which are published on my technical writings blog.
This is the place to leave comments on those writings. The relevant postings are:
KNIME and beginners, where I walk through my problems trying to get heavy atom counts working in KNIME