I was using Cerave vitamin C 10% serum for over a year. Loved it and still do actually. It works well for me - sometimes even instead of a moisturizer in the morning. I was just feeling experimental this week and ordered Paula’s Choice Vitamin C 15% booster. I’m excited to see if I’ll notice any difference in skin brightness. On the first application, it’s definitely less hydrating than the Cerave one (no surprise here). It has a distinct smell, and I weirdly like it. The skin feels a bit tacky after it, but sunscreen went on nicely. I’ll report back in a couple of weeks.