My youngest son missed the cutoff by about 3 weeks but went to kindergarten on schedule. After a few weeks the teacher proposed moving him to first grade because he was reading on a 3-4th grade level, proficient in math, etc. He was also very physically and emotionally mature (bigger than all but one first grader, tutoring the other kindergarteners, etc.).
When I told my father he was skipping a grade, he was concerned because it could make him less prepared in sports later on. While I understand the rationale, the chances of him being a collegiate-level athlete in the future are fairly slim and were not worth him being horribly bored during elementary school.
We considered all aspects - my middle son had been proposed to skip kindergarten as well but he didn't have the physical and emotional maturity to match his intellectual maturity so we declined. IMO we made the right decision with each child.