Interesting answer to my question, I have to admit for myself I usually (emphasis on usually) get more bang with knights, probably considering my general strategies. All games are different, of course (and I occasional have "blind spots" when a piece goes into my bishop's line of fire, particularly if I am setting something else up)
And to answer your question:
the latter, if the pawns are close to the other side, and I can turn one or more into queens.
One situation I find myself in against computer opponents.
Sacrifice the queen?
getting the opponent's queen off the board vs keeping your own queen on the board