Im one of 4 and I have 4. It was really hard at first when my baby showed up. But things are going pretty smooth now. I had my four in 6 years so they are pretty close in age.
They do play nicely when they pair off. But im looking forward to my baby being able to run around and join in with the big 3. I also considered the rollercoaster aspect as we like to do Disney every year or two. Baby 4 has been such a blessing. She is the sweetest baby. We sort of planed on 4 kids. Im not willing to say im done. But we are done for now. Might go for 2 more in a few years. See if I want to start over again lol.