I haven't forgiven Suqqu for discontinuing their Eye Shadow Brush S before I had a chance to get it. I still dream of it in a way only other obsessive makeup brush collectors will understand. But their larger Eye Shadow Brush M, while not a replacement for the mythical S, is a fabulous tool in its own right.
Made of extremely soft gray squirrel hair, featuring an elongated domed head, Suqqu Eye Shadow Brush M is tightly packed and relatively firm. Technically it's a crease brush that applies quite a bit of color in one go, but the shape and hair also make the brush suitable for blending and diffusing product upwards.
You can see that in terms of shape and (head) size, the brush that comes closest is the Eye Crease brush from Le Metier de Beaute. It's an excellent performer that has more give than the Suqqu, thus making it brilliant for blending but somewhat less so for a cut crease (it's all relative, of course. The LMdB brush is a staple for me). Next, you can see that both Chikuhodo Z10 and Hakuhodo Kokutan T that are considered cousins of the Suqqo S are decidedly more directional as they should be-- they're smudge/smoky eye/lashline brushes. Hakuhodo Kokutan T and its twin G5528 are denser and firmer than Suqqu M.
Bottom Line: an excellent and hard to duplicate brush.
Suqqu Eye Shadow Brush M (48GBP ~$75) is available from Selfridges in the UK and select locations in Asia (also at ichibankao.com with a considerable markup).