This Quo brush will forever consume me. I don't have it in me to throw it out, I just can't do it. The brush sheds like a freakin cat. every time I run my fingers over it a black bristle comes out. this brush is definitely NOT a 187 dupe. The white bristles have much more give to them and this brush is way fluffier. When you wash the brush, it takes quite a long time to dry - about a day and a half because it so dense. I've used this brush about three times and washed it about 5 and it still sheds.
The brush normally sells for about $23 but I got it for 40% off because of a sale. Aside from this brush I'm really happy with all of my Quo brushes, they're really good quality and minimally shed if not at all. The one thing I really REALLY like about this brush is the handle (the same with all other Quo brushes) its so thick and easy to hold its not flimsy at all.
I'm thinking that at some point this brush HAS to stop shedding, either that or it will end up completely bald because I'm not giving up on this one haha.
Bottom line - I think that in order to make a 187 dupe out of this brush it will require lots and LOTS of work - so in general its not worth it. Although I don't own one Sigma has from what I understand a good dupe of the MAC 187 - its called a SS187.
Overall - I really dislike this brush, it sucks. Don't buy it. I'm rating this brush half a Glitterbomb out of 5 only because I like the sturdiness of the handle.