I've been using this serum for three months now, twice per day.
It's really easy and nice to apply since it's absorbed immediately and gives the skin a nice hydrated feeling (like it drank water indeed). Exceptionally useful during travel, I keep a mini version of it with me on the plane for a frequent lightweight super fresh moisturization.
However for combination skins like mine I didn't notice visible changes, but it does feel nice on the skin to use it before a moisturizer.
You can always count on it for a fresh lightweight hydration especially during hot days.