Tokyo Ghoul is a very unique series. Tokyo Ghoul is set in a world where ghouls, creatures that feed on human flesh. A shy college student named Kaneki is going on a date with a girl named Rize, but after her revealing that she is a ghoul, there was no going back. After leaving Kaneki to the brink of death, she was hit by some metal bars dropped from a building. After that Rize's organs have been transplanted into Rize, making him a One-Eyed Ghoul. Now, Kaneki must survive as a ghoul by using his powers, and to further polish them. It has a lot of character development, ad a unique story. It had a pretty good art direction, but I think that the series went a bit downhill with the premiere of season 2. Studio Pierrot did a fairly good good job on adapting Tokyo Ghoul, but I have to point out a few things. In season 1, they switched the Gourmet Arc and the Dove's Emergence Arc (I guess Pierrot wanted Ryouko to live for a little while). They left out important plot details (like how Kaneki learned the technique to easily break an arm=, and don't get me started with season 2! Season 2 left aside Touka (this also includes Kaneki on the first episodes. Please take in mind that he is the protagonist) leaving her with little screen time, and it focused a bit too much on CCG. It also focused on a story arc that differed from the other half of the manga.
Leaving all of that aside I would say that this anime is worth watching, but make sure you read the manga first. Maybe if Studio Pierrot, stayed faithful a bit more to the manga, it could have gotten higher ratings (and would have stopped the request for Madhouse to reboot Tokyo Ghoul). Nevertheless, Tokyo Ghoul is one of the most successful horror series. With Tokyo Ghoul :re (the manga sequel of Tokyo Ghoul), they both have reached 22 million copies in circulation, and some people say it levels up to Death Note.
Leaving all of that aside I would say that this anime is worth watching, but make sure you read the manga first. Maybe if Studio Pierrot, stayed faithful a bit more to the manga, it could have gotten higher ratings (and would have stopped the request for Madhouse to reboot Tokyo Ghoul). Nevertheless, Tokyo Ghoul is one of the most successful horror series. With Tokyo Ghoul :re (the manga sequel of Tokyo Ghoul), they both have reached 22 million copies in circulation, and some people say it levels up to Death Note.