I bought this on either the Sephora Black Friday or Boxing Day sale for $10 or something and it is my HG eyeliner! It is so creamy, it works great on the tightline and lashline. It's easy to sharpen to a bit of a tip so you can create amazing winged eyes.
Many people compare it to the NYX Slide-On eye pencils and although they feel similar in application, the MUFE has much longer staying power and is more of a true jet black! There are days where it literally lasts 24+ hours on me and when I fall asleep with my makeup on (oopsie!) it still looks pretty much the same as it did when I fell asleep with only a little bit of fading on the inner bit of my lid.
I don't use it on my waterline, however I know my sister likes to not blink and let it set for around a minute and set it with a translucent powder or a good quality black eyeshadow and that seems to increase the time between application and wearing off.
I would highly recommend it for anyone who's sort of on the fence about trying it or venturing into MUFE.
Unfortunately, I don't think it's a great product for me. I know a lot of people love this formula, but I have a hard time making it show up on my waterline, and it fades and smudges quickly and unevenly. It's much more even and pigmented if I use it on my lower or upper lash line, but the staying power, while decent, is not fantastic. It also smudges, but much less so.
Now, my eyes have a tendency to be very watery, so I have much better luck with harder textures (think Chanel Le Stylo if that helps -I know some hate them for this reason, this is what makes them rather good products on me, but I should mention I have never found an eyeliner which performs excellently on my waterline), but Aqua Eyes eyeliners are probably too creamy for me.