The Panasonic LVF-1 Electronic View Finder (EVF) is awkward - The Panasonic GF1 is a beautiful compact camera and the add-on EVF makes it bulkier. The EVF is useful, especially in bright light, but I did not care for it because of the additional bulk and its low resolution. If I do use an EVF, it will be on another m43 body such as the Panasonic G2 or Panasonic GH2 which both have high resolution, built-in EVF's.
The Olympus looks cooler and is more compact, but only has an add on viewfinder.
The Panasonic G2 / GF2 have a built-in viewfinder, which may just be the thing that tips the balance for me.