My sons kindergarden teacher suggested that he repeat it, although he was being released from special education services. He was reading at a 3rd grade level but has behavioral issues and due to his OCD she thought that he wouldn't be able to keep up with the rest of his class. I chose to go ahead and put child into first grade and see how it progressed. I figured that I could have him repeat the grade if he didn't do well. His first grade teacher was absolutely shocked when I told her half way through the year that it was suggested for him to repeat kindergarten as he was progressing so well.
My thought process was to let him have the opportunity to succeed before assuming that he'd fail.