What do you want your serum to do? Different serums do different things.
Skinceuticals Phloretin CF is my favorite. It is an antioxidant serum for day so it is anti-aging, helps with sun damage and builds protection to the sun. I also use Skinceuticals Hydrating B5 serum in the morning -- it is for moisturizing.
At night, I use Makeup Artist's Choice DMAE serum, which is a more straightforward anti-ager.
They all do different things, so I don't think that there's one right answer.
ETA: I don't use glycolic or retinoid serums because I use a glycolic toner in the morning and Retin-A at night. If I didn't have already those ingredients in my daily routine, I might want serums that include them. They're fantastic anti-agers.
Currently I'm using one love organics love springs eternal. I think it's pretty basic - moisturizing with some anti aging. It also claims to "detoxify" skin by helping the skin push out stuff in pores. Honestly my pores do seem better. But I'm also on retinol products.
Skinceuticals Phloretin CF is my favorite. It is an antioxidant serum for day so it is anti-aging, helps with sun damage and builds protection to the sun. ETA: I don't use glycolic or retinoid serums because I use a glycolic toner in the morning and Retin-A at night. If I didn't have already those ingredients in my daily routine, I might want serums that include them. They're fantastic anti-agers.
That one sounds great but the price tag is a bit high for me. I only use serum at night since it is too much on my face for day. I want anti-aging. Building protection to the sun sounds pretty amazing though.
I use Origins Plantscription serum for Anti-aging. Its $75 but I only buy it when on a sale, which Origins has semi-often. (they also have Plantscription eye cream and moisturizer, dont mix them up!)
I break out from most. Every time I've tried a sample of something else, my skin freaks out.
not really related, but once I'm done having kids, I plan on going on Retin A, but my derm won't prescribe it to me while we are TTC.