Pros:
-Far better characters than the previous three generations, including rivals.
-Terastallization was a surprisingly fun feature, and I love how Tera types were implemented in gym battles
-Fun to ride around on Koraidon and Miraidon
-Obviously, the open world is a step in the right direction for Pokemon
-Excellent quality of life features (quick heal, quick battles)
Cons:
-The game runs VERY poorly (Poor general framerate, game doesn't handle multiple characters on screen very well, graphical glitches)
-Poor overworld environment graphics
-Far less outfit customization
Conclusion: If you are a Pokemon fan, get the game, you'll enjoy it for the same reasons you enjoy any other Pokemon game, with the added bonus of an open world. If you are not a Pokemon fan, don't bother - the game runs so poorly that you will likely be distracted from any redeeming qualities that the game offers.