So glad to see this thread kicking off (by which I mean, becoming populated by adult, balanced and intelligent conversation).
I absolutely love co-sleeping with DS. He starts in his cot, but always comes to bed with us at midnight or so, never cries at night, bfs a couple of times (or nonstop if he's teething or sick, like now), and cuddles like crazy. Then in the morning, he grabs my hand and says "mama," and pulls me out of bed. I can't think of an easier or more lovely way to start the day!
He's very secure and confident. He's gone to a new nursery today because his normal carer is sick, and he settled in without any trouble, just waved bye-bye to my mum who dropped him off and went in with the other kids to play, to I am not at all worried at extended bf or/and co-sleeping are stunting his development. Quite to the contrary, I think, but who knows; perhaps he'd be exactly the same if he'd been sleeping in his own cot from the start and started out on formula.
The other thing is, as I just wrote that I realized, that kids are so different from one another. DS never wanted to sleep alone, some kids don't like co-sleeping. Same with bf; my friend's DD weaned herself at 12 months, just lost interest, while DS is a boob-monster. So we find our way, with our particular kid, and whether it makes a difference or not is just something we can tell ourselves when we're really stinking tired from a night of kicking/bf-ing, or having to re-settle LOs in their cots.
I just really liked the article, the way it was mostly unapologetic, and normalized the idea of co-sleeping just a little bit.