In the continuing absence of hands-on primary experience, maybe this will help with the E-P1 size debate. A regular reader who's become a friend of the site sent me this illustration he made. He took the images from various places on the web but they're presented scrupulously to scale. (Personally, I think each of us should just wait to judge until we see and hold the camera for ourselves. But we're here to please.)
Left to right, Canon G10 (1/1.7" small sensor), Olympus E-P1 (Micro 4/3), Canon 450D (APS-C), and Canon 5D Mark II (24x36mm or "full-frame"). Click on the image to see it a bit larger.
Featured Comment by JK @ Studio Hatyai: "For close to a year, c. 1992, I carried a Fuji 6x9 rangefinder around Tokyo pretty much every day. It was a fairly big, clunky, noisy camera, but within a few months I stopped noticing those things, as you do with something you’re using all the time. The curious thing was, most of my subjects seemed to stop noticing it about then too. Somehow they were picking up on my casualness with the thing.
"Ever since then I’ve quit worrying about the exact size, color, shape etc. of a camera, at least in terms of its potential discretion. Much more than anything else, subjects respond to your ease with your gear, and your ease with them."
Mike replies: I had a weird experience once with that very camera that confirms part of what you're saying. I had one for a few days to try, and I felt very awkward and nervous pointing it at people. One time, believe it or not, I pointed it from my 4th-floor balcony at some nearby construction, at one guy working on a roof, and as I was looking through the camera the construction worker looked right up at me and glared. It seemed to me at the time like he had sensed himself being watched or spied on. It was uncanny, but I don't think it was a coincidence. Although it might have been, of course.