Huh? It's an optical rangefinder that zooms in tandem with the main lens. Like any rangefinder, there are parallax issues if you're close to your subject.

I always have more problem with camera with two separate optical systems. I like my viewfinder to show me exactly what the sensor is seeing. It has to be a SLR like TTL viewfinder (for example the Olympus E20) or an EVF for me.

I shoot everything with the flip-out screen

I really dislike using flip out screens to shot pictures, I can't get a good feel of what I am looking at. I can see how they can be useful in some situations though.

It all comes down to personal preferences really and I need some kind of TTL viewfinder on my camera. That's what I have on my current Olympus and I couldn't go back to using a compact camera style viewfinder again.