Despite the comments I saw, I bought it.
I wear it for everyday/morning at work as it is not as intense as another one I have for evening looks. The brush is perfect, you put it on like a pen and it lasts a long time. As someone who is not familiar with makeup, it took me 2-3 times to figure out how to hold it because I was used to a pencil. It removes very easily and overall it has good staying power, it doesn't run. Just to give you an idea, I apply it at 8 in the morning for work and remove it at 9 in the evening when I get back. It stays put, doesn't smudge, and comes off easily with washing. That's it...

I use eyeliner daily for over a decade. I bought it for the promised properties, although the price was steep. It doesn't have intense color and the brush is not wet enough to facilitate application. I need to go over the same spot several times to avoid gaps. It has great longevity, but it is difficult to remove. It requires a lot of persistence, multiple passes with cotton and makeup remover, and finally a wet cotton swab at the roots of the eyelashes to clean completely, whereas the previous eyeliner I used, unfortunately discontinued, could be cleaned with foam wash. I think I will stop using it before my eyelashes fall out!