My oldest two are all within years of each other. My oldest two are 11 months apart, and the middle two are 6 months apart. (We're a his, hers and ours family)
When they were little, there were times when it was frustrating. I started raising my oldest two when they were 1 and 2. I potty trained all three of them at once. Which at the time was horrible, but now that I look back, I wouldn't have done it any other way. On the other hand, they were always playing with each other. For hours on end, they would play. I could get housework done without a problem! Plus, they were all best friends (and still are). You better believe anyone messes with one of them, and they're messing with all of them.
Now, my youngest is four years younger than the third child. When she was little, the kids wanted to help with her, but then the newness wore off, and they didn't want to deal with her again until she was about 2 or so and could run around and play with them. Now she can go upstairs and play with them so it's not so bad.
I enjoy having my kids closer together. I'm finding it difficult to finish school when one is still at home at all day, expecting to be entertained. Next year, they'll all be in school.
Something just dawned on me...I'll have three teens learning to drive all within 18 months of each other...my insurance is going to sky rocket!
It's all about personal preference. There are pros and cons to each. Good Luck!