You said everything i had in my mind Melainie.. couldnt have put it better myself!
Jesse was exactly the same. He had a local needle, cried having his nappy off and having the needle and then stopped. Was fine during the proceedure and sat in the waiting room talking his head off afterwards. He never from my observation, sufferred any trauma. He wasnt physically able to make a sound at all.
I mean if you search enough you can find studies that are pro both ways, i think it just depends on the author's opinion of which is best, so i think its just a personal decision for a parent to make on what they personally believe is best for their child.