Age range difference between children

My son will be turning 5 in February. People have brought to my attention that I shouldn't have kids so far apart in age and I'm not sure whether to believe this as my partner and I are not ready to have a second child quite yet. I have two sisters and all three of us are 4 years apart and it turned out to work quite well when it came to getting along. So my question to all of you is.. Do age differences between children have a positive or negative effect on children when growing up? I understand there are pros and cons to everything but I'm more interested in what your personal experiences have been. Thanks!