Much as I expected, I didn't manage to finish Saints Row 2 in less than 20 hours, but I am pretty close. I just finished off the third of the main gangs, the Sons of Samedi. This series of missions isn't quite as compelling as the other two, as their leader, the General, isn't quite as well-drawn a character as Maero or Jyunichi. There's a few good moments with him and Triple Platinum DJ Veteran Child, where the General is far too intense for his gang's hippy facade, but a lot of opportunity was squandered on a sagging kidnapping plot that weakens Shaundi's character unnecessarily.
The Sons of Samedi do have the advantage of being the silliest of the SR2 gangs, but they're a little to self-serious to really pop as comedic characters. They're sort of in this weird limbo where they don't quite fit in with Saints Row: The Third's wacky rogues gallery, but they also don't have enough dramatic meat to fit in with the other SR2 gangs. That being said, Saints Row 2 is a game that doesn't quite fit in with itself, so I have no real problem with them. If anything, I would have liked to see more of them. Oh well.
I'm at 20 hours, but I'm going to finish out the game. I only have a few Ultor missions left to complete and I might as well see the whole story before starting Saints Row: The Third.