Here's a fourth option for you. I just leave mine alone. I like the added "floor space" as a brom allows for more space that was wasted before. Although in one of my tanks, a pup is growing in between the mother plant and the background. I'm wondering if as it grows if it will push the mother plant off of the background. We'll see.
I have always heard when they are at least 2/3 the size of the mother. I got one I need to cut off. I also read that once you do cut off the pup it helps promote the mother to producing more pups. But you can kill the plant too by doing it prematurely so I try to not get to exicted to cut mine off.