I have heard some people say that it is harder to go from one kid to two than from two to three and vice versa. So, what do I think? I think that at least the first few months with a newborn are going to bring about their own challenges. But putting that aside, I would have to say that it was probably harder for me personally going from one to two than two to three.
One thing I found out in going from two to three was that I really needed to get more organized. That is still something that I struggle with, but I do have a basic system in place now. I don't always keep my schedule exact, but I follow it the best I can. And when I don't, I notice that there is a lot more chaos in the house.
The other factors that come into play with my particular situation is baby temperament, and possibly gender. My third baby has been much more calm than the other two, although my second was still fairly easy-going. As far as gender goes, I don't know what it is like to have a toddler girl, yet. But, I do know that having toddler boys is pretty wild and loud. I don't know if I am being gender-biased or not, and forgive me if I am. But, it does seem that boys are more difficult through the toddler-through-elementary years than girls are. But, I have heard that girls can be more difficult teenagers. I would think that the teen years are going to have their own issues, and gender wouldn't affect them that much.
Anyway, where I am now with the kids is a fairly decent place. I can actually see the boys making progress in their behavior, and R hasn't hit that stuff yet. So, despite moments of chaos, I would say that going from two to three is manageable if you take things as they come.