I was at my local art and office supply store and I saw the Pigma Brush Pen. It was pretty cheap, so I bought it on a whim.
The “brush” is less a real brush and more an elongated felt tip pen, a lot like the Tombow Brush Pens. This is clear when you compare the Pigma Brush Pen to an actual brush pen, like the Kuretake. So you can’t get the big swells of a real bush (unless you drag the tip along its edge and even that is limited). So what you get here is something halfway between a brush and a marker.
Still, the control is nice. The pen is really easy to use and less messy that the real brush pens. I’ve been having a lot of fun sketching with it in my notebook.
I have read on-line that some people have see the pen fray after use. That hasn’t happened to me, but I’ve seen this with other felt tips.
Overall this is a nice, very portable little sketching pen. The quality of the ink is good and its archival. Still, don’t assume that you’ll get a real brush feel with this pen.