Dh and I are tossing up #4. For me personally I can think of so many cons. Another mouth to feed, child care/school fees, less time to ourselves/other children, so a lot more cost and being time poor. However, I still have that niggling feeling for just one more. Initially it was to try for a boy, but I know we will most probably have another girl and I'm cool with that. I love having a big family, I'm one of eight and I liked that friendship siblings have growing up.
So my husband asked me last night if I thought I could cope.... I said yes, but really how do I know? Is it that much difference? Things are easier now dd3 is older. We would have a larger gap than usual as we have waited til now to decide. Dd1 starts school next year, dd2 is going to kinder. Its going to be busy... there's always buts though!