[M.B.E.]

I would call. In this type of game, when the flop comes queen- or jack-high your QJ will be good often enough to get positive expectation. That's my current belief, anyway; I'm open to being persuaded otherwise.

<font color="purple">Would your answer be any different if you were in late position? How would it change if you were in a tight game with only 2-3 players taking a flop on average? </font color>

In the loose game I'd also call in late position.

In a tight game if three players limp ahead of me then QJo should be folded. Now the chance is too high that someone has KQ and/or AJ (perhaps KJs).