Yesterday I borrowed the viewfinder VF-3 with a colleague. I usually have the VF-2 on my PEN E-PL1.
After half an hour I have given up trying to compare the two, the VF-3 falls to from very!
Sure, you can lock it and whether the side diopter adjustment is better than that of the VF-2 is a matter of taste but in the really important disciplines wins the VF-2 by a mile!
Although a precise adjustment of the sharpness level at macro photography possible with both but the viewfinder image of the VF-2 is much brighter and more detailed.
In strong sunlight the VF-3 then darkens as strong, which is not an accurate assessment of the image possible. The lights fray more than they do the VF2.
All in all, the VF3 is therefore worse than the VF2 and still cost the same? I think that's outrageous! As already mentioned by my outpost: A price of 99 would be appropriate and the only way he could also be near the VF-2 !.
If so pending a viewfinder for Pen: Take the VF-2: The really worth!