The series beautifully and dutifully nods to the comics. The acting is great, the casting choices are incredible, and the plot follows the plot of the comics closely. It inhabits its own interpretation while still being wholly faithful to the essence of the characters, story, and the comics' aesthetic.
(Sorry that this next section is a little vague, I'm trying not to include specific examples which could spoil moments in the show)
You do not need to read the comics before the show; it stands alone strongly. However, there *are* some nods to scenes which were either cut or not yet explored in the show, scenes which the comics spent significantly more time on. Unlike many other comic or book to screen adaptations, these moments don't feel as if they're deviations from the plot. They're not included just to show that they read the comics, these moments actually satisfy long time readers' cravings which longed to see these tidbits in film form. They also appeal to new watchers faithfully, continuing the idea of exploring the multitude of stories told in this same world.
They also left an opening for a season 2 while allowing viewers to rest in the completion of the story of season 1. There is a cliffhanger, but it's not cheap.
I really truly loved this adaptation. I've been recommending it to everyone I've been able to convince to let me talk about it for more than 5 seconds, and it's rekindled my love for the graphic novels. I love Neil Gaiman's work, and the show is faithful to it while being accessible to newcomers with no context.
Little tip: this is NOT something to put on in the background. It's very much a dramatic mood watch, you need to be ready to immerse yourself in the world or you're not going to enjoy it.