@Chris Cree @Albert - Until 3.6, Post Formats were half baked and because the User Interface for them was not exposed, at least not like what we'll see in 3.6, adoption of Post Formats has been low. I think they went this route to expose the feature to more people and thus, get more folks to use them or at least investigate what they are. In my opinion, Post Formats add one more step in the publishing process if you're not going to use the standard format.

@Mark k. - You make a great point, especially about expectations. One of the drawbacks for me that I didn't mention was that I was not sure how the content would look until after I published it. Hitting the preview button shows the content within the single.php page template therefor, not allowing me to see the content post formatted. This was frustrating and was another reason why I stopped using them.