As a serum I don't Think it's great, but I do love use it as a primer before makeup. It feels silky smooth and leaves the skin poreless, and I believe it helps the foundation to stay on better for some reason. Its just a small bottle and used up quite fast, I found myself reach for it way more than any other primer that I have, this must says something.
I feel pretty neutral on this product, so since it's nothing spectacular I probably won't repurchase. It goes on smoothly, but I don't think it completely absorbs into the skin. It dries quickly though, so you aren't left with a sticky feel, which I like. If I'm going to use a serum, I'd prefer it to contain ingredients that I'm sure are beneficial to the skin, and I really don't know if I believe the "science" around "PhytoCellTec Malus Domestica." I like to use it before makeup because it does smooth the skin, but the effects are temporary, like a primer. It also feels skin-firming, but again, the effects are temporary.