DD1 and DS are 25 months apart. I really struggled when they were 3 and 1. I questioned why I wanted such a short age gap. Both in Nappies, both very dependent on me etc. They got along great once they hit 4 and 2, but life was still very full on.
DS and DD2 are 47 months (just short of 4 years) apart. I love it! The gap has been a blessing. DD2 has been the only one in nappies, I have been able to focus solely on her as her older siblings have been more independent. When she was 20 months old DS started school, so she has had me to herself for 4 months which has been great for our relationship. Her older siblings are also able to help out a bit more around the house as well so its not so overwhelming.
I am about to have a (surprise) gap of 31 months between DD2 and #4. I'm hoping the gap will be just as rewarding as our previous one.