You may or may not be aware that I am a huge fan of Shadowhunters (not the show, the books). I started reading Mortal Instruments when I was in middle school, right around the time book three had come out. I picked City of Bones up on a whim and quickly discovered that it was one of the best books I had ever read. Since that point I have avidly kept up with the books (recently reading, reviewing, and loving Lady Midnight) and this year even plan to reread them all. A few years ago when the movie came out I was super excited for it, but my dreams were crushed by the film itself. While it wasn't the worst adaption I've ever seen (Vampire Academy steals that award) it is up there. Which led to me starting this show with a mix of fear and excitement.
As a show: It's not a good show. The acting was pretty bad when it started off (though all the actors did grow throughout and I'm rather fond of them each as people thanks to social media) and the special effects are absolutely atrocious (I'm sorry, but the seraph blade noise comes from the toy section of Target). The sets are all really nice, the story lines are interesting, and the world building is on point, but if I hadn't been a fan of this story ahead of time I wouldn't have even given it a shot.
As an adaptation: Better than the movie, if you ask me. They stuck to the plot more or less, but where they deviated I think they made smart decisions. Things were introduced early, but they weren't half-assed when they were introduced. The world that Cassandra Clare created in her books is this same world. I liked that while the core of the story was there I was able to be surprised by certain plot lines and my friend and I have been guessing at what next season might bring (and yes, I am rather excited for next season).
As a fan: I'm thrilled. Okay, mostly thrilled. Beyond it being a poor quality show (but it is on Freeform so it's not like they have an HBO budget) I love being able to see the characters come to life onscreen. These are characters I've been reading about since I was 13 and 14 years old! I think the casting for characters was pretty spot on and easter eggs (pretty much that whole alternate reality episode if I'm being honest) are a blast. Seeing the fandom on tumblr just explode over these books again has been really great, too.
Would I recommend this show? If you're a fan and you're willing to wade through some shit (maybe a lot of shit, depending on how much you want the show to adhere to the books) I think you'll enjoy it. I haven't met anyone who's watching the show without reading the books first, so I don't know if it's a good fit for people who aren't aware of the world. Maybe give it a shot, though?