Upon encountering one of N's Pokémon, the game will notify by showing a sprite entry animation that is similar to the Shiny Pokémon sprite, but instead has its own sound and the Pokémon is surrounded by green and yellow diamond lights. This animation will be overwritten if it becomes a star at Pokéstar Studios. The flavor text will read "Awild <Pokémon> appeared?!" Upon being captured, the game will notify the player that the Pokémon already has an original Trainer, before putting it in the player's party or PC storage. Once captured, the Pokémon will have N's ID number, 00002, thus they gain the boosted experience that traded Pokémon do. These Pokémon cannot be nicknamed since they have no Secret ID. N's Pokémon have a set nature, and have IVs of 30 in each stat. They are incapable of being Shiny. Whilethere is only one of each Pokémon,ifthe Pokémon faints or the battle is otherwise ended without the Pokémon being caught, it can be encountered again
-Bulbapedia
I think the 30 iv deal is pretty nice overall. Some set natures might even be good and it can save you a lot of breeding.
