The Magicians is a pretty irreverent fantasy series: the whole point of it is to be subvert common fantasy tropes, like the idea of a heroic Chosen One and magical boarding schools being joyful experiences. The books are so snarky and subversive, and I wasn't really sure if the TV show would be able to capture that without being grating and annoying.
I can't really say if I like the books better or the TV series better, because they each do some things better than the other. The TV series made the main cast of characters a lot easier to relate to, and the casting was absolutely perfect. I found Quentin a lot more likable in the first season of the show compared to the first book. In the book he is just so broody and directionless and depressed (which is the whole point, but it's still tough to get through a whole book of angsty Quentin). Quentin on the show is all of these things as well, but the faster pace of the show means he grows out of it quicker and it's less painful to watch. The first season of the show is also more dynamic, weaving in story lines from the first two books instead of only focusing on the first book. That means we get a lot more screen time with Julia early on, and I found her story more compelling in the books, so that was a welcome change. I also absolutely LOVE Margo (Janet) and Elliot on the show. They are so sassy and preppy and just absolutely perfectly cast.
Another thing the show does better than the book is being more explicit about how racially diverse the main characters are. Penny is played by Arjun Gupta, who is of South Asian descent, and Margo is played by Summer Bishil, who is biracial. In general the minor characters are also pretty diverse, and there are quite a few queer characters on the show. At the same time though, the show can sometimes miss the mark (in one episode, for example, a queer WOC is introduced and then dies in order to further the development of a white woman).
As much as I enjoyed the first season of the show, I feel like the second season started to grate on my nerves. It's tough to play a character like Margo or Elliot and still maintain a level of emotional complexity, and there were some scenes where the actors did a great job of that and other scenes where I just wanted Elliot and Margo to shut up. The same is true for Alice, I liked her initially but once she becomes a fixation/hallucination of Quentin's she's pretty painful to watch too. I think the sarcastic tone of the show just got too grating to me. It's so much more obvious and in-your-face when you're hearing quips from a bunch of characters instead of reading biting social commentary in between the lines of a book.
There was also the whole Marina storyline which was so unnecessary. But if that storyline is the reason Kady is in the show, I'll deal, because Kady is easily one of my favorite characters. She's smart and resourceful and doesn't take shit from anyone. I loved seeing her relationship with Julia (best bitches forever!).
The books grew on me and I liked each book better than the last, but I felt like I couldn't stick with the show after two seasons. Each book sees the characters grow up and make sacrifices, but on the show everything seems too flippant. Maybe this will change with later seasons, but I definitely need a break from the show for a while!