This review is by Kalina Wilson, who can also be found at Geminica.com.
The Sailor Pocket Brush Pen (Super Fine) isn't really a brush. It's even less of a brush than most brush pens of the type. In order to provide a line that could be described as "Super Fine", Sailor got rid of all the brush-like attributes and has simply provided a fine felt-tipped pen.
I don't mean that as a complaint, really. The pen works well, the tip is performing well so far (I've seen one review that claims the tip doesn't hold its point for long, but haven't seen that problem yet myself), the ink is waterproof, and it seems to be a good workhorse product. If I wanted to draw comics with a consistent line instead of the variability you can get from, say, the Tombow Fudenosuke which I unabashedly love, this super fine Sailor would be a decent option.
However, I will not buy this pen again. At $2.25 (JetPens), it's the same price as the Tombow Fudenosuke. The Tombow has a much nicer body made of recycled plastic with crisp, professional printing on the side; the Sailor is made of cheap plastic with sloppy silver printing on the side. It just looks and feels cheap. The Sailor Super Fine will give you a more consistent, thin line compared to the Tombow Fudenosuke's variability, but if consistent line width isn't your top priority, the Sailor brush loses its only advantage. Personally, I just wasn't very excited to pick this one up, but will probably keep it around and use it until it runs dry because it performs a simple function and works fine for what it does.
I haven't tried the other sizes of Sailor brushes, and they may be very different from the Super Fine so there is further investigation to be done.
If you're a fan of the Sailor Super Fine brush, I'd love to hear about your experiences with it and whether the tip has held up over time.
Note: Drawings on this page are based on Victorian mugshots, which are easily found online and lots of fun to browse.