Compared to GTA, Saints Row 2 has the opposite approach to the sandbox aspect of the game. In GTA, you unlock new games and areas by doing the story missions. In Saints Row 2, the world and its amusements are open to you from the start, and you must earn the right to progress the story by playing the mini games.
I like it better, as it focuses more on playing the game buffet style, picking what you like and doing lots of it. And there are a lot of things to do. (All of the stuff I listed in the comic is stuff you can actually do in the game.)
Although, it did get sort of boring after a while. Once you've murdered your way from the suburbs to the financial district, going streaking seems sort of tame. This is a game best played in short, bloody, earth-scorching sessions, not a game you binge on.
Shamus Young is a programmer and writer by trade, videogame nitpicker by inclination. If you have the patience for more of his ramblings, they can be found at ShamusYoung.com.