Now the name can kinda be a bit deceiving as it isn't really a 'serum', and it doesn't really feel like a serum, the only 'serum-like' quality i think it has is the way it smoothly applies on the skin.
Firstly, the packaging is great, it's plastic and light so great for travel and the fact that there's a pump makes it 10x better so you can get the exact amount of foundation you want. The consistency and coverage is pretty great, i'd say it's a light-medium coverage, but definitely on the more medium side as it has a lot more coverage than a tinted moisturiser, the consistency isn't very thick so it's blends beautifully into the skin. The wear time for this foundation i'd say for me is about 10 hours-ish and then i start to look a bit shiny in my t-zone. The shade i picked was Light Vanilla (51) and it's pretty much a perfect match for me, it's like a pale yellow-ish shade which matches my skin perfectly as a have some yellow undertones in my skin. The scent might be off putting to some people but i don't really mind it, it's kinda fruity and definitely beats the normal foundation smell you get from most drugstore foundations. I like to use my Real Techniques Expert Face Brush to apply it and work it into the skin, but i find using my hands also works just as well.
Overall out of 10 i'd give this a 9/10 as it's literally almost perfect, but the smell can be off putting sometimes and it can be a little runny in consistency but overall it's a brilliant foundation!