Between 10 months (although preferably walking) and 3 is my favorite age. I like when they start just before the first birthday. That way I can "train" them, for lack of a better word.
I loathe caring for school age. I thought it would be easier, but I would take a cranky toddler over a bratty 5-10 year old ANY day.
I don't mind doing diapers, and the little ones still nap!! Aaahhhhh. Quiet time.
PS> LOVE love love what playfelt said above. If this little guy is here full time, it should not take more than a couple weeks for him to settle down. Longer if he is only part time. Allow him to cry, unless he is hurt or something like that. Pat him on the back, remind him he is okay, and continue on. The more attention he gets from this, the more he will continue! We don't want to be cold and unsympathetic, but it will only make your day harder if he keeps this up!