Not the best.
Pros: landscape, towns, music and new pokemon designs, storyline and wild area concepts and the gym challenge.
Cons: lack of an immersive storyline, inconsequential grunts, lack of depth to the main 'villain's' motivation, abundant cut-scenes, hand-holding (albeit slightly improved from S+M), rail-roading, linear routes and lack of dungeons, lack of side quests or npc challenges, quick and dull post game.
I feel like the game is represented well by the cities within it, they appear busy and full of life, and yet empty at the same time.
While personally Dexit for me is not an issue - anyone with half a brain could see was going to become a problem for years - it feels like it could have been handled better. Maybe having 200 (give or take) new native pokemon and regionals and exclude all older pokemon to save arguements?
But why not just widen those time targets Game Freak? I'd rather have a quality game than a new gen within 3 years of the last....
Oh that's right, because it's a guaranteed money maker...
All in all, it's a 'nice' game, but incomplete.