This isn't going to be a long post. I'm just going to refer to a post I made in July about Managed Identity Services being a hard sell.
If you haven't read it, feel free. If you have, someone made a comment in response to it which I've also responded to which extends the discussion a little.
Incidentally, if you want to keep track of the comments people write, here's the feed. Unfortunately, it's only available for those using RSS readers. Those of you subscribing via email will have to do without it for now. Sorry :(