While the second game is a flat-out huge improvement across the board from the first game, the third entry in the series is more of a tradeoff in strengths.

The narrative is more complex (for better or worse), the animations improved, the characters have even more personality and the locations are more varied. However, none of the improvements are very significant. On the bright side, the downgrades to the music and level design are likewise not significant either.

Personally, I would rate it just as good as Sly 2, but with a weaker ending and some tradeoffs in strengths.