Where has this mascara been all my life? I will admit I was skeptical about using a primer on my lashes before mascara but this works well together. It's too bad L'Oréal doesn't offer this in a two pack of individual full size tubes (one primer, one mascara). I did a fair amount of research before purchasing, I've never used tubing style mascara before but I was really tired of flaking and smudging with regular mascaras, not to mention it's allergy season and my eyes itch and water like crazy. I found that the best way to apply this is with a thick/generous coat of primer (this provides some volume since tubing mascara generally only provide length) and before the primer dries apply the mascara over top. The mascara coats and covers the primer easily, no issues with white primer showing through, and gives insane length to your lashes. There is ZERO clumping, even when applied with a heavy hand. There is ZERO smudging, ZERO flaking, etc. This stays in place all day long and come off easily with just water-soaked cotton rounds.
A couple of issues that you should consider before purchasing is that with this much product on your lashes you probably won't hold a curl all that well. I'm not talking stick straight lashes but definitely they will droop some. The other thing that another reviewer also mentioned is that it's not the blackest of mascara but I believe this is because of the white primer base underneath. This is not an issue for me but if you are looking for intensely pigmented jet black mascara you won't get it with this product. What you will get are super long, clump-free separated lashes that will not irritate your eyes, will last all day without flaking, smudging, smearing, etc.
If you haven't given tubing style mascara a try yet, this is an affordable entry point and I recommend testing it out before venturing into the high-end brands.