I’m pretty new to the serum game, so I can only go with my limited experience, but this serum seems to deliver what it promises. Compared to the other Vit. C serum I tried, it does not leave a sticky residue. I appreciated the instruction to rub it in thoroughly (which might have helped with the last product). It also does not irritate my skin or cause clogged pores, which seems to happen with some products. It doesn’t have much of a smell, but what it does have is neutral, certainly better than the retinol serum that I use. I’ve seen other reviews criticize for not having a citrus smell. I feel that adding an artificial ingredient for the purpose of allowing someone to “perceive” that it is what it says it is (e.g., citrus= Vit. C) is not a good idea, because there is more risk of adding something that will irritate the skin or otherwise work against the product, so I’m in favor of keeping the serum as natural as possible.