I just checked out the E-P1, here are my initial observations, bear in mind I only had a few minutes with the camera, it really takes a lot more time to carefully evaluate details.
1. LCD performs well in bright light, of course others may disagree, but I believe it is more than up to the task. Can you shoot with the sun directly shining over your shoulder into the LCD? No, but that is a rather rare occurrence, it's fairly easy to shift the angle of view and recompose, indirect bright light is not a problem. I didn't see any issues using the lower res display.
2. Autofocus on the kit zoom has more vibration than the Pansonic kit lens, but seems to be about the same speed, certainly fast enough for me.
3. The rep did not have the 17mm or the viewfinder, he did have the flash and the 4/3 adapter (but not the OM adapter.)
4. Manual focus works very similarly to the G1 -- press the info button, then ok, then use the thumbwheel to use 7x or 10x magnification
5. I tried putting a Pen F lens on the camera but the RJ (Jinfinance) adapter does not mount. I will try the Hawk adapter and some M adapters next.
6. I like the menu interface, it appears to have two sets of them, one more akin to point and shoots and one more like the Oly DSLRs, so whichever way the user is coming from, the camera can accommodate.
7. The Panasonic kit lens worked fine on the Oly, the Oly kit lens worked fine on the Panasonic.
8. I really like in body image stabilization!
9. The E-P1 is actually smaller than the original Pen (in this case a Pen FV.)
10. I like the stainless steel.
11. The control dial is pretty slick, it can rotate (ipod-ish) or can be operated with top/bottom/left/right button press.