Not to give the wrong impression, the Miwaku is a very nice pen. The horn material is "warm" to the touch, somewhat like wood except harder and smoother.
The shape is "organic" yet elegant. Your eyes are caught by the curvaceous lines of the pen and your gaze lingers (much like curves of a different sort).
The pen feels balanced in the hand unposted. It is heavier than a celluloid pen, but I wouldn't describe it as a heavy pen. It does feel quite substantial in the hand. The amply proportioned section widens out into a even more generous barrel. Holding the pen has the feeling of encircling a shapely derriere with the crook of your arm.

The flexy fine nib produces very expressive lines. The flex is pretty good, on par with some of the vintage flex pens I have tried. The nib writes smooth, although as I mentioned before, it tends to start dry. There's just the right amount of feedback for me.
It's definitely a pen I would see in my regular rotation, despite a couple of blemishes.