Pro The character development is quite impressive
Dragon Ball Kai features some really great character development. While Goku, the main character, doesn't get much development, you also have characters like Vegeta. Vegeta goes from super villain, to begrudging ally, and beyond through the duration of the story. There are also characters like Gohan, Goku's son, who goes from a peace-loving scholar to arguably the strongest hero in the universe.
Dragon Ball Kai is often underestimated in the story department, but it's really quite rich and overall incredibly entertaining.
Pro Fast paced and action packed
Dragon Ball Kai is a remastered version of Dragon Ball Z, and it's taken significant amount of useless content out. This makes Kai much more fast paced, which also means there's less time between fights.
Dragon Ball Kai is jam-packed full of fight scenes. You follow the "Z-Warriors," a group of people presented with the dubious task of protecting the earth, and there are certainly a lot of threats, each more powerful than the next.
Con It cuts a lot of content from the original
Dragon Ball Kai is a remastered version of Dragon Ball Z. The fact that they cut a lot of filler out was really great - it lead to more action, and an overall smoother flow for the show. However, some of the filler that was cut was really incredible, and people that are watching Dragon Ball Kai as their first experience will miss out on some classic scenes.