"Lens slap"...my bad. I meant mirror slap, of course.
The G1 has an EVF, and it's quite good...for an EVF. Nothing like a good SLR or a Leica (I have both), but not as bad as some people imagine. I find it quite useable.
As far as holding the E-P1 away from your chest, it depends. I had exactly the same initial bad reaction when using small point-and-shoots, because I didn't use them that often. With the EP1, however, I've developed my "chest" technique -- that is, I brace both of my elbows against my lower ribcage and look at the target over the top of the camera, which is perhaps 6-8 inches away from my face. Sometimes you have to move the camera a bit for framing, because your hands aren't always looking exactly where your eyes do (as with a VF), but you quickly adjust. I wear bifocals (the continuous kind) and have no problem focusing on both the target and the LCD, because the LCD rather naturally falls within the scope of the "near" vision part of the glasses. The biggest problem is that in switching from one to the other (target to LCD), you have to take your eyes off the target, if only for a second or two..but again, you adjust. It's not perfect, but it's not a nightmare, either.
Shutter lag -- the G1 seems as fast to me as a DSLR, in both manual and AF modes. The E-P1 seems to have a bit of shutter lag (not usually enough to be a problem) in manual mode. The AF, on the other hand, is notably slow, and *can* be a problem.
But the cameras are quite compact, and the IQ is excellent. The zoom lenses are slow, but that the price you pay for the compactness. The E-P1 has a 14-42 f3/5-5.6 zoom that I like for its compactness, but I don't like that 5.6 on such a short lens. But using that lens, you get a very useful wide range (equiv to 28) and a nice portrait range at the long end (equiv to 84.) The equivalent G1 lens is a bit longer (14-45) but the same speed.
I have an adapter for my Leica M lenses, and shooting a Leica 135 on manual mode is a hoot -- I can focus more quickly and more accurately with either of the m4/3 cameras than I can with an M7 or M8. Same with the Noctilux.
The ISO is okay, but nothing to write home about. In general, it seems to me to be about a generation behind the Nikon/Canon standard...maybe a stop or so?
The coolest thing is traveling with it. I can put both bodies and five lenses, which will get me from 7 (equiv 14) to 200 (equiv 400) in a small Leica bag, and it's lots lighter than the Leicas. I can get the whole thing in a no-questions-asked carry-on, along with a Mac Air and all the bits and pieces, along with the rest of my travel stuff. (And I have quite a bit of stuff -- extra glasses, prescription meds, usually a novel or two, etc.)
JC