Fun, but it gets repetitive once you beat the main-story.
Anyway, you go through the game as whatever Pokemon the game picked for you and the partner you picked, completing missions and adding members to your team. All 1st-3rd Gen Pokemon make an appearance.
After completing the main-story you're free to roam around, recruit legendaries, evolve, whatever you want. At this point I lost my incentive to play because I completed all the goals. I may pick it up again someday, though, it was a fun game.
I recommend this game to any of the remaining nostalgic Pokemon fans, current Pokemon fans, and that's probably about it.