One of the best manga out there right now. As I'm writing this, an anime adaption has just been announced, so I hope it starts getting the attention it deserves!
That being said, this story has several core strengths that it uses to its full advantage, the first being it's interesting premise. If the blurb wasn't clear, the basic idea is that a 26 y/o loser gets sent back 12 years in the past, to when he was in middle school, in order to save the life of the girl he dated back then. That's pretty standard stuff, nothing very interesting unless you're very interested in time-travel stories. Where it varies is in its subject matter: most of the characters are delinquents. To avoid spoiling anything not said in the blurb, I'll just say that there is fighting, desperate struggling, and it is hopelessly touching to watch the characters struggle against "the future" and their own pasts.
The characters are probably this story's greatest strength. It's the kind of plot that's completely driven forwards by the characters themselves, but that doesn't feel forced. I have yet to come across a story that feels so full and rich without having some greater plan in play (if you think I'm wrong, or have suggestions for a similar type of story, please let me know!). It feels so startlingly real, but you never lose a sense that it couldn't possibly be real; that'd be too much. The story is full of shounen tropes, but instead of ruining the characters, it adds to a sense of familiarity. From a technical standpoint, almost every single character is almost lovingly developed--you can see that the author has a great deal of affection for their characters (even though they get hurt pretty badly). The character designs are memorable, and I love each and every character individually, all for different reasons.
The art keeps surprising me as well. Despite going for a "cartoonish" look, which at first was off-putting, it actually displays an incredible depth of emotion. I can confidently say that the art style suits the story and that I can not imagine reading it if it were to get another artist.
tl;dr Tokyo Revengers is an absolute gem of a manga and deserves hype. I am incredibly excited for the upcoming adaptation, and highly recommend this to anyone at all-- it doesn't matter if you've read 2 manga or 2000.