Big pair means QQ+ but lets get a couple things out of the way first. In no way am i saying that limping is better the raising. At micro stakes raising is always better as they call down so light. At least it is in a vacuum. Limping does have a few advantages though. For one it disguises the strength of your hand. Also it always you to play more drawing type hands cheaply. People will be less likely to punish your limp if they remember that just just limped with aces a few hands back.