I'm really shocked that nobody wrote a review on this one yet so I'll break the ice for now.
I need to make this clear from the beginning: If fighting isn't your thing, drop this manga, it's not for you.
If you read the prequel and liked it, you'll love Tough!
But even if you started with this one, you won't be dissapointed, you don't really need to know what happened before to appreciate Tough!
As a fan of martial arts/full contact I can assure you that this manga is the real deal.
I was really impressed by the art.
I love all the characters in Tough!, antagonists included.
The most impressive one is Kiichi of course, he's what I would call a "real man", someone who'll respect his principles and promises no matter what.
The characters may not be developped too deeply like in other mangas but as I mentioned before, Tough! is a fighting manga, too much words are useless.
Delightful to read thanks to the fights and the art but again, I may be repeating myself, this only applies if you're into full contact.
No need to explain why, this is a paradise for those who like/practice MMA.