There are some changes. Some character's combos are different, and there is no more Overdrive, 50 meter cancel, or universal overhead in Rising.

Also rising has dash attacks, Bravery points, and ultimate skills that this version does not have.

But if you intend to buy Rising, then you can practice with some characters to get used to their moves, and progress in RPG mode will carry over along with unlocked weapons/skins, so there is a reason to play this to scratch the itch until next month