I don't have the Pen but have the Panasonic version which is the GF1 - as you've probably gathered it's a mirrorless camera using the same size as sensor as the bigger 4/3 Olympus/Panasonic SLRs. I'm not actually that keen on this size of body as I don't find it much use, although they look small in pictures in reality they're quite bulky and only barely smaller than the G1/G2/G10/GH1 cameras and quite a bit bigger than the likes of the Panasonic LX3. They only make sense with the pancake lenses of which there are just two, the Olympus 17mm F2.8 which is a fairly poor lens both optically and it's slow or the excellent Panasonic 20mm F1.7. Another 14mm pancake is on the way buy that's about it, the lack of grip on the bodies makes it difficult to balance a zoom particularly the heavy but flexible 14-140mm.
I prefer the slightly larger GH1 as it offers an excellent builtin viewfinder, a decent grip, articulated screen, multi-aspect ratio sensor and better movie capability. I don't find the GF1 is small enough comfortably in a pocket so as I'm using a shoulder bag anyway I prefer having the better capabilities of the GH1, I still use the LX3 as my pocket camera to keep with me at all times. Although it may seem pointless getting the GH1 style body as it's not that much smaller than the smallest SLR bodies, the lenses are a good bit smaller so my overall micro 4/3 setup is far smaller and lighter than my SLR one.
Of course that's just my opinion which is the opposite to some people who prefer the smaller body and find the larger ones pointless.
John
