This sh*t is the BOMB. I have to admit, when I purchased this, I didn't expect much, considering its brush looks like the type that does nothing but separate (ahem, Maybelline One by One), and my previous experience with mascara primers were not so good, but this? Oh, man, this stuff really is awesome.
Like most lash products, the first coat really doesn't do anything. You have to layer on multiple coats to achieve the full effect. The second coat, for me, gave a substantial amount of length, but the third and fourth coats really give me super incredibly long lashes, and it actually curls my lashes! Can you believe it? Something other than an eyelash curler actually curling my lashes! And my lashes actually stay curled the entire day!
Unlike face and eye primers, however, this doesn't prolong the wear of mascaras, nor does it prevent smudging and clumping. In fact, that's not the purpose of mascara primers at all--the purpose of them is to add additional length and volume to your lashes, so that your mascara can add even more legnth and volume. It basically acts as a "booster", in a sense.
I find that this product is the key to achieving the dramatic, huge lash effect--I can virtually pair this with pretty much any other mascara and have good-looking lashes, but I personally think it works best paired with the Dior Diorshow Mascara (say hellooo to ginormous lashes!).
Of course, it's not very cheap retailing at $28, but for a mascara junkie like me, I think the price is rather worth it.
Would I repurchase? Definitely.