Well I won't speak as to the possibility of this thing being a scam, because that's pretty well covered, but I will talk about 4/3 for a minute.
I recently entered the dSLR market and picked up an Olympus E-500 (before the 400 and 510 came out) with a 14-45mm lens for a hair under $500. I have since picked up a 40-150mm and a 35mm macro. Both lenses were fairly inexpensive, and I have been very pleased with their clarity.
I love my camera, and can take great shots with it. I feel that the lenses I have picked up are more than sufficient to hold me for a while, which is definitely a good thing because there's aren't a whole lot of truly inexpensive lenses available for 4/3 (I consider "truly inexpensive to be $300 or less; I know some people consider $600 to be inexpensive, but I'm not one of them).
I will also agree that the viewfinder is relatively small. I haven't had a whole lot of trouble with that, though, because I only use manual focus to tweak the auto-focusing, and I get very good feedback re: the shots I have taken on my LCD. I also don't think the size is significantly smaller than what you get on other cameras, and you can always pick up an eyepiece with magnification (assuming your camera has replaceable eyepieces - mine does).
I do, however, disagree with milo's comment about DOF. I have had no noticeable problems getting a DOF that was either as large or as small as I wanted it to be. Granted, I had some difficulties in the beginning, but that was more my own misunderstanding about how open or closed my aperture needed to be for certain things.
Finally, I will suggest to you what I suggest to anyone considering switching to 4/3: check out the website.
Four-Thirds
Look at the bodies and lenses available for the standard. Then check out the prices of the lenses. If you can get what you want from what's offered now (I suspect there will be more choice in the relatively near future, but you can only bank on what's out there now), I say go for it.