There are a few things that you should probably know about. The first is that reborn has a level cap which increases with each leader you beat. Once you pokemon level up past the cap they will not obey you. You can buy an item called common candies to lower them back down. The second non-vanilla thing you should probably know about is field effects. Reborn adds a lot of new field effects and improved the few that exist in the vanilla game. You will be able to get more info on these changes as the game goes on. Third, hidden abilities are available in the wild and can be changed to with an ability capsule. Finally reborn resprited most (if not all) of the shiny pokemon and increased the shiny rate. There are some other more minor changes that are probably not worth listing. All of these changes are explained if you talk to certain npcs in the game, even the minor changes.
