Since i am a veteran photographer from the ancient days of film, I prefer shooting using the electronic viewfinder. Of course I use the monitor if I am doing a high angle or low angle shot. When I am shooting portraits on a tripod the monitor is very helpful. In this situation, the monitor gives me the ability to interact 'face to face' with my subjects and capture their best expression.
If I am hand holding the camera and the subject is moving or I am moving, I find the viewfinder helps me obtain a more precise composition. The other advantage to the viewfinder is that when you shoot at slow shutter speeds, bracing the camera against your face with your elbows close to your body gives you the ultimate support for a steady image. If you are holding the camera in front of you looking at the monitor you are definitely going to be shaky.
Which do you prefer, and why?
I agree with you and @monica Ira. I am EVF all the way... Being a landscape photographer, the edges are very important to me and looking through the EVF with my non-shooting eye closed down, I can see my edges very clearly. I try to eliminate bright tones and parts of external elements that don't belong.