I liked Saints Row better than San Andreas, too.
The level of customization you have generally blows it away, and you're not forced to do the storyline to unlock areas, stores, or anything else. There are a few annoying missions (I hate trying to drive and shoot at the same time), but not in the amount that SA had.
Plus, SR2 will have co-op campaign, which makes it a huge DO WANT in my book.