We have 16mths between our first two. I found it pretty difficult for the first 6mths in particular, but up to a year was pretty tough. I suffered with AND and PND, which made it all the more difficult. My children are terrible sleepers, and having two that don't sleep well, a very frequently feeding breast fed baby, a DH who worked 12+hr night shifts, and having to return to work part time when #2 was 5mths old was really difficult.
But now looking back at it all I love how close they are to each other. They are a bit like twins in how close they are and they miss each other terribly when they are separated. I love their relationship and how close they are to each other. They do drive each other (and me!) bonkers sometimes, and are now getting to the stage of tormenting each other (at 5 and 3 1/2), lol. But that is what siblings do and I don't really think it would be much different if they were any further apart in age. Their adoration for each other far outweighs how they torment each other, lol.
I wouldn't change it at all now. Had you asked me in the first year, I would have said I would have preferred that they were further apart. But that was in the think of my depression and struggling with work ect. It was all circumstantial and mostly due to lack of sleep. As I got more sleep, I felt better. I love how it is now.
As for sleeping when they were tiny, we had DD (eldest) in the cot and DS1 int he cradle for about 4mths, and then we brought DD a big girl bed. by then she was pretty much too big for the cot anyway. She transitioned really well into the bed, and DS1 ended up cosleeping full time anyway!