It's a shonen sports series about boxing which is known for the intense action sequences. Normally I can't stand shonen battle series, nor do I care for sports, let alone boxing. Hajime no Ippo stands out because the character development is excellent, for both the main characters and their the opponents who are all fleshed out people with believable motivations, not just 1 dimensional villains brought in for the current fight, as you get in most shonen series. It has a lot of comedy elements too, so it's not just GARR all the time, but the show knows when to be serious as well, so it's not overplayed. This is probably the best sports-related anime ever made.
^^This.
I rewatched One Outs recently, a show about Baseball, and I'd say that's on par if only because it doesn't drag on forever and there isn't a RETARDED half-assed romance subplot floating like a flaccid ghost in the background.
There's also 'Hajime No Ippo: The Fighting!' which I've seen on Crunchyroll, it's far more fighting focused, I would heartily recomend you watch it if only for the visceral impacts.
That's just legit just another section of the manga, as are all the movies.
But yeah, I really liked Hajime No Ippo, but I swear, when I dropped the manga, Ippo was on his way to being the first World Boxing Champion while still a virgin. It's awesome to see such a such a lowly guy like Ippo work his way up and make himself into the manly awesome boxer that he is, but it's just straight cringe-worthy when he fawns over this one chick who's ostensibly saving himself for him, and he has plenty of opportunities, but it's just played up for laughs because apparently remaining sexually infantile is just the pinnacle of comedy. It badly detracts from Ippo's character because every other character is developing, except for HIM, so as you progress through the story you see Ippo just getting better at boxing and every other part of his life and personality is neglected.
I know it's a Shonen, and it's alright for guys to be kind of a dweeb and awkward when it comes to the opposite sex, but this gag goes on for what is literally years and years of Ippo's life, and at a certain point you just resent the writer for being so lazy and refusing to either finalize it or kill it, but instead this romance joke remains in limbo for what I presume will be the day Ippo actually dies of old age.