I'm always looking for new brush pens, and in the year or so since I've had this
one and many others like it, the Akashiya Sai outline pen has definitely been
the one I've used the most. It works great for marker and watercolor work -
doesn't smudge, dries fast. The bristle head is the perfect size for the smaller
scale work I do, and you can get good line variation out of it. It wipes the
floor with most of my other pens, and while I love the Pentel pocket brush pen,
the last three I've gotten were total lemons. For the price and consistency, I
prefer the Sai.
As already noted, the only drawbacks are that the ink isn't the darkest and it
isn't refillable. But when this one runs out of ink I'm going to try it as a dip
brush with my Kuretake ink and see how it fares. Regardless, I love this pen and
will continue to use it for most of my drawing needs.
I ADORE this pen. Out of the few I've bought and tried from this site so far,
this has been the clear favorite. As has already been noted, it isn't
waterproof, which was distressing the first time I tried to watercolor over a
drawing done with this pen. Oh well, lesson learned. Seems to work fine with my
copics. Lovely lines. The best non-bristle brush pen I have ever used.