I saw a ton of people with them last week at GDC Online (formally, and more properly named GDC Austin). Heard they were pretty big around VMWorld too.

I had one guy ask me about the iPad when I was sitting in the expo area. 30 seconds later he was sold, simply by me pointing to the battery indicator and explaining "This morning when I got here, it was at 80%, now it's at 50%, after 6 hours of note taking and internet browsing".