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To paraphrase the WIRED article, the 5 reasons are smaller size, great quality of images, interchangeable lenses, speed of operation, low-profile, but are expensive.
By the way, EVIL stands for Electronic Viewfinder Interchangeable Lens. It also seems that with an adapter, these cameras can accept many DSLR lenses.
I am extremely interested in these cameras, particularly the Lumix GF1 (above), and will certainly look into on my return from India.
(Via the always informative The Click.)