1. Once you hit the green button to cycle to the MF mode, does it stay in that mode until you power off (i.e. in between MF shots)? I assume it is no longer in that mode after power off/on.
The camera stays in that mode until you change it. The settings are retained on power off. This is an image view display mode.
2. "You can also set the Fn button to toggle between MF and AF." I guess by doing this, you are effectively reducing it to 2 button presses to MF zoom, just like the Panasonic G1.
Well technically a single button press. The swtch is a direct toggle between MF and the last AF mode you were in. For exmaple, on the next press of the button after entering MF - if you were in C-AF, you return to that mode, if you were in S-AF, you return to that, if you in S-AF+MF, you return to that one.
When in any of the modes, other than when the zoom view is displayed, you can also use the standard AF control on the 4-way pad to cycle between all settings.
3. When zoomed in, do you find the E-P1 LCD resolution to be just as effective as the Pansonic cameras? I'm thinking if you routinely use MF zoom, then the resolution difference is not as significant.
I cannot comment as I don't have a Panasonic camera and have only used the G1 briefly and not for MF. I find the LCD perfectly adequate for use focusing. All you need is something with a bit of contrast so you can see it. I regularly work at night with no lighting other than ambient moon light or distant street lights. I do find that lenses of f/2.8 and faster help quite a lot and I also have the LCD set to gain up automatically.
The only problem with the latter is that when using graduated filters, you can really see the effect. I am guessing that this must therefore affect the range of shades on the LCD but other than using graduated filters, have never noticed this to be a problem. That is really digressing a bit as it isn't related to using the camera for MF.
4. When not zoomed in, do you get that 'edge shimmering' when the subject is in focus? That is a somewhat useful way to confirm focus too.
No. The image is nice and crisp when in focus and you can easily determine the best point of focus by moving the focus ring either side and then choosing a mid point - just like on a convential mat screen viewfinder (sort of). In many respects, the manual focus reminds me of my original Nikon F with its full-mat focus screen.
I am quite happy with the MF on the E-P1 but cannot compare it to the Panasonic cameras. Yes, a higher resolution LCD would be nice and so would the ability to change the angle. In general I find the angle of view and general use outside of the LCD to be the best I have used on any camera and it is an easy camera to live with.