The generational aspect of each saga means a complete story is told with every arc. The adventures generally feel more mapped out than other stories, or so I think.
All the characters have skill sets with mindbogglingly specific utilities and flaws, and its amazing to watch them be challenged and overcome those challenges.
Its flamboyant in ways that you wouldn't expect anything to ever be, even though the male characters are usually very buff and masculine.
Most of the main characters are named after bands and musicians, at least in the sagas I've watched, and its great.
It has a great sense of humor, often derived from its stoic and manly looking characters having deceptively quirky and deep characterizations, not to mention the bizarre nature of their abilities.
Despite all of this, its surprisingly grounded compared to your Yu Yu Hakushos and One Pieces. Its set in something resembling the real world, taking place in a rough amalgamation of our history and in real life locations. The second saga takes place in 1938, and the Nazis are already causing trouble around the world.
Its really violent, closer to Fist of the North Star than the more kid friendly violence of Dragon Ball and the like. Expect decapitations, graphic breaking of limbs, and some stuff that defies easy explanation but boy does blood spew everywhere.
Villains are menacing and ruthless (the thoroughly evil Nazis are by no means the most evil force in part 2, for instance) and the stakes are generally high, especially as each story comes to an end.
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Remember that during the crisis, the heroes were not politicians, CEOs or billionaires, but doctors, janitors, and service workers. Now, who is disposable?