I have two 22 months apart, and I have to think a lot of how having closely spaced kids works out depends on the family and on the personalities or any issues with the kids.
My kids are now almost 3 and 1, and it still feels like the older sibling is adjusting to having his baby brother around. I think it might be easier to deal with a second child when the kids are in daycare or at least if there is some help available. As a SAHM, there is only one of me, and my two year old didn't stop needing tons of my attention when the baby arrived. A two year old can't be counted on to be nice to a baby (even for an instant). A two year old may require lots of attention and discipline, which may require letting a little baby cry more than you would like. An easy pregnancy with a toddler to care for can be hard enough, since there is no longer the option of just resting when you are tired, and if you are caring for two once the baby arrives, napping when the baby naps might not be an option.
My husband is bothered that he has little interaction with the one year old in part because our older child really wants his attention when he is home. The days of having just one baby seem romantic in retrospect because my husband and I were doing so much together as opposed to each of us focusing on a different kid (and as SAHM, my breaks these days mostly consist of having only one child to deal with at a time, not with having time truly by myself.)
That said, it is getting easier, and I am hopeful that my two will enjoy many years of playing together and enjoying many of the same types of activities. We didn't seriously consider child spacing issues because I was already over the hill (40 when I had my second), and I don't regret having them fairly close together. I can't imagine having them closer, but I know many families do. I think it might have been easier to deal with my oldest (a personable but sometimes difficult kid) if had been an only child for another year, but I like that, even now, he doesn't remember life before his brother arrived.
Now, how am I going to get through today? :)