Do you side with Saadia or with Kematu?
It is quite modern these days to let players make decisions in video games - and like so often before, the decision doesn't seem to matter at all, except economically (like in GTA IV).
Second modern thing: switching sides. I mean - isn't it funny: at first you meet two Alik'r warriors in the city - they tell you, they were looking for a Redguard woman. Though they feel somehow strange, you think - why not try to find her for them. Then you find Saadia by chance - and she tells you, she's being molested, so you switch sides and go hunt Kematu and his men. In "Swindler's Den", the gang immediately tries to kill you, and I had a hard time getting through to the boss. You talk to him - of course, he puts it his way, and soon you switch sides again - I believed his story, and followed his orders, and finally I found myself back in the city lying to a woman that I'd do everything to protect her, only to lure her out of the save walls and hand her over to a gang, that tried very hard to kill me just before.
The motives are simple: Kematu tries everything to reach his goal: at first you as a stranger are recruited on the streets by his men; in the cave they try to kill you when you come for them; when that fails, you are suddenly again trustworthy enough to be told something, to make you a tool of his wishes, to lie to and cheat on a defenseless woman, who trusts your judgement blindly and follows you to her doom. No explanation whatsoever is given, why his men tried to kill you in the first place, if their motives were so pure; and sadly you cannot ask about that.
I gave him the blade. The bastard won't be missed in MY Skryim!