An aspect which is not covered in the reviews is manual focus which is only available with the Pentax and the Olympus I think. These are travel cameras and the ability to lock the focus at infinity is important when shooting from an airplane or car window.
The best feature I found with the iphone is the touch focus and exposure. Great for back lighting - I usually take 2 shots, one for the main subject exposure and the second for the background - assuming I do not move, much.
How can you discuss the impact of smartphones on photography and not mention touch screen focus and lighting (as with iphone)? I am waiting for a real camera to have this excellent feature.