I have noticed a significant difference between the two main version of bid for position script, there is the original iWeb tool clone which uses alphabets and there is the second generation phplink bid seem to have developed which actually categorised sites into Arts, Computers etc.
My observation so far is that PR flow in iWeb Tool ABC clones seem to flow better (sub pages have excellent PR for example A Pound A Link , afpilot.com ) and example of the second script such as BigWebLink and other.
I wonder why?