Rode with the iPhone in my jersey pocket yesterday. It fit well in my old Timbuk2 strap pouch that I carry in my jersey. Also fits their large cellphone holder for shoulder straps.
As other reviewers have found, the iPhone is a breakthrough device that does all that you’ve read or heard about. I’m struggling with the touchpad now and I’m not going to try and ride and talk with it for a while (not that you should do that anyway).
Check our Photostream for a set of photos taken with our iPhone.
My daily shooter is Sony a9 with a vertical grip and various Sigma lenses attached like the 14mm 1.4 Art. Find more recommendations on our store page.