From about 3 - 8 they are the greatest things ever, a non-stop source of entertainment and fun. I never thought I could love something as much as I loved them at that age.
Mrs WES and I once had a discussion over a bottle of red about what age would you freeze them at if you could. 8 and 6 for us. No downside at that age and they are still a joy.
Anyone who doesn't want children has no soul.