I had a Pen EES which took nice half frame pictures, although I ended up converting the exposure mechanism for more manual control.
My biggest disappointment was that it tool half frame pictures in a portrait orientation with the top and bottom of the picture next to the perforations. What I really wanted was a camera that would naturally take pictures in the old "filmstrip" format that all us old timers remember from our K-12 education days. This requires a picture with the sides of the image next to the perforations The Pen could do this but you had to hold the camera in a vertical orientation all the time which I found unnatural. The Pen looked like any other rangefinder camera with horizontal film travel. Because almost all filmstrip projectors have a vertical film travel they need the pictures to be positioned in a horizontal orientation. The following blast from the past describes the "filmstrip" format and its relationship to the half frame cameras.