Have to admit that i still love the age gap of 18 months between my oldest 2. It is hard at the start but is so easy now (well would be if i didn't have #3!). I think it would have gotten easier around a year ago (like i said, if i didn't have 3) because the older 2 play together so well for hours on end and entertain each other, but then they did do that from when #2 was about 18 months old so maybe i was just lucky. They do have off days where they fight all day then it's bl**dy awful but mostly fine.
Hope it gets easier for you soon
Julie x