Thanks to Kensington for sending me their Sling Bag. It's everything I hoped it would be -- and a real buy at $19.95. I really wanted an over-the-shoulder case because I take my iPad everywhere with me. The Sling Bag is fashioned like a messenger pouch so that it rests in the small of your back. It leaves your arms free, and stays in place even when you bend over to do things.
One thing I wondered about was how convenient it would be to grab my iPad out of the bag if it's on my back. The bag easily slides around so that you can access it. And since the zipper extends across the top and down one side, when you slide the bag around in front of you, the opening is still on top even though the bag has rotated to a horizontal position. I was astonished by this touch -- it gave me the feeling that the bag is well engineered.
It's sturdy and well padded. Inside the main pouch is an additional padded, Velcro-enclosed compartment that's just the size of the iPad. There's also a zippered pocket that covers almost the entire face of the bag, and within that is another Velcro-enclosed compartment that's just the size of an iPhone.
The only thing that I didn't like about the Sling Bag was that when I shortened it a bit to accommodate my 5 ft 8 inch height, it left a length of strap hanging in front. But I figured out a way to neatly fold that over.
The image from their website shows the bag over the left shoulder, but the one they sent me goes over the right shoulder.
Update: I really liked this case, but it wore out after a few months of hard use: fraying and coming apart at the seams.