I bought Beyond Good and Evil from GOG this past Christmas. It caught my eye because the ratings for it were consistently high from both critics and customers everywhere.
I agree! Gameplay is great! It is a bit of point n'click adventure, action, stealth and strategy all in a well-balanced game. Aside from saving the world, you also take on assignments to take pictures of animals or other things. It can be challenging as not all subjects are easy to find or reach.
The world in which this takes place is vast and beautiful. The whole place is a great joy to explore because there are a lot of hidden surprise things to do.
It might not be ready right out of the box though. I experienced screen tearing and extreme lag, but happily, those were easy to fix!
Highly recommended! Get it!