The extensive Pokedex and library reference guide are almost worth the price of admission alone. Add to that, the capability of the Transfer Pak to access Pokemon from the Game Boy versions and things really begin looking up.
The Pokemon Academy section of the game was brilliant, and the mini-games are a lot more fun. What it boils down to is this: Did you play through Gold or Silver? Did you enjoy battling? If so, you will love this game. If you did not, pass.