Soundimageplus have written a short essay about viewfinders, comparing different types, such as optical prims finders and electronic live-view finders, to one another.

In essence, what they find is that an electronic live-view finder, such as on the Panasonic GH2, is far better in most circumstances than the optical viewfinder of an entry-level DSLR — which are often very small and dark and thus virtually useless in low light.

You can find their article here.

Personally, I’ve grown quite fond of the viewfinder of my Leica M8. Especially in comparison to standard DSLR finders. When I had my old Pentax ME, the finder was very large and bright. And this camera wasn’t a “pro” model in its day. When I look through a normal DSLR finder these days, I find the experience totally unenjoyable. Of course, rangefinder viewfinders have their drawbacks, but for me personally, I prefer them over any other type of viewfinder.

Looking through the M8’s viewfinder, I see a large, bright and clear picture of the world. I see framelines helping me compose, and I see a rangefinder patch helping me to focus accurately even with insanely fast lenses. You can’t really manually focus on a DSLR, and you can’t either on an EVF as long as there isn’t a certain amound of depth-of-field left.

Yes, I’m a rangefinder fan!