Just bought an electronic viewfinder for my NEX-5N and am realising just how much photography has changed (for the better). I now have a tiny, weeney camera that takes photos as good as most DSLRs. I can put almost any lense on it (30 year-old or pretty new). I can set it to aperture or speed mode and select the ISO. Scariest thing is though that I can select the speed and aperture and ask the camera to select the ISO ...
... that's like changing the film on the fly in the old days :)
I now have a camera that is as portable and quiet as a Leica, yet gives me the viewfinder of a SLR ... really, this is the best of both worlds.
BTW: Sony charge £320 for the viewfinder, yet you can get it shipped in 2 days from Hong Kong for about £200 ... still scarily expensive, but feels worth it.