I agree.. No perfect age gap. BUT my pros of having them close are.

You have baby stuff already around so no need to find, rebuy pack up etc as you already have it.
You are busy but wiht 2 at the same time.. and once they get older things get easier,
My DD and DS are 19 months apart and DS loves his little sis to pieces they share a room and cannot get enough of each other.

Cons, Financially can be hard on families,
You are getting 2 kids into car seats..
You are maybe waking to 2 kids at night.

I have made a pact with myself to only ever have 1 kid in nappies at a time.. and i have done just that!