Peak Pokemon, without a shadow of a doubt. How can any generation even come close? The culmination of every advancement of every generation prior into one solid ass motherfucker of a region. Only region to have sequels. No mandatory EXP share. No 'dodging the attack because it loves you' bullshit. Respectable difficulty. Throws a middle finger to the Gen 1 fan service. Great Pokemon designs, great stories. Features to spare. Didn't have shiny odds and devalue shinies altogether (although it DID introduce shiny locking, a genuine negative)

And you know it's the best, because people to this day are still arguing whether or not it's the best. Kanto, Johto, Hoenn, Sinnoh, Kalos, Alola, and Galar, fucking kneel.