I bought a three pack of these liners on IHerb for only $3 and considering the cost, they are incredible products. However, if I was to ignore the bargain factor I would like to point out a few issues.
I got a plain black, a gold glitter and a silver glitter liner in the pack. The black liner is very watery and it's quite hard to build into a solid line. To remedy this I had to fill in the line with another liquid eyeliner by Coral Colours - luckily both are matte black so they blended well. I'd also say that the glitter in the gold and silver liners should be a little finer, as I think that would look better on the lid. Those are the only 'cons' that I could see, and they're pretty minimal in the grand scheme of things. There are far more things to love about the product than there are to loathe!
The applicator wands are amazing, I wish all liners were made this way. The black liner has a very fine pin point brush that makes it easy to create a variety of liner looks! Usually I find it hard to get a precision line with most liquid liners as they have a felt tip style applicator - but not the e.l.f liner! It is really awesome :) I found that it was great for creating wings and drawing the eyeliner outline, which I then filled in with a 'felt tip style' liquid eyeliner. Even though I need to use two different products, I think the overal effect is worth it.
I also found that I could line my eye with the black and then put an overcoat of gold or silver liner on top without making the undercoat run. This meant I could create some really striking eye looks!
In terms of wearability, these liners stay put all day! They may be watery when first applied, but once they dry they're there to stay. Best of all, they are as easy to put on as they are to take off! Just wipe with a cloth and they're gone, no panda eyes afterwards. These benefits, along with the price, make this a product worth trying
Moving from a pen eyeliner to this, I am very happy with the result, my winged line is so much more smooth, defined, and darker than when i used a pen. I do find that the end of the brush is quite long and a bit square rather than tapered into a point, which makes it harder to get a really sharp point on my wing, but it is awesome for the price.