The Sailor Profit Brush Pen comes in a simple packaging with two spare ink cartridges.
The design of the pen actually matches their Sailor Profit series of fountain pens that are recognisable by their torpedo shaped body, gold-coloured clip and trimming at bottom of the cap. In fact, you can swap the brush tip and grip into a real Sailor Profit fountain pen. I mentioned "real" because the material for this brush pen is plastic and feels much cheaper compared to the $100++ Sailor Profits. But it does not look cheap.
I feel that the Sailor Profit Brush Pen is more prone to giving thicker lines. As in, it requires greater care to control the thickness of the strokes. Kuretake is the sharpest because the bristles are longer and tapers to a really sharp point. Pentel Pocket Brush is somewhere in between but easier to work but the ink flow is not as good as I want it to be.
The ink in the ink cartridges provided are waterproof. If you buy them separately, make sure to get the Sailor Kiwa-Guro cartridges. You will save a lot of money if you just get the bottled Sailor Kiwa-Guro Ink and use the refillable Sailor converter.
Sailor Profit Brush Pen has a good ink flow. Lines always come out dark with sharp edges. For dry brush effect, you have to draw really fast.
The three sketches above are drawn on the Daler Rowney Arteco paper which has a slight textured surface.
Both the Sailor and Pentel brush pens are quite affordable. The Sailor cost more by a few dollars but if you get the bottled ink and converter, it will be cheaper in the long run. Pentel uses only disposable ink cartridges so you have to keep buying them.
If I have to choose between the Sailor and Pentel brush pen, I would choose the Sailor because it has better ink flow.
Kuretake is for those who want finer things in life.
Anyway, check out my ultimate brush pen comparison too.