With all classes, I'd say the Bladed Scarf is better.
It doesn't have a style that is alignment locked, like the Starknife's Divine Fighting Technique from Desna. Not every class can be Desnan.
Beyond that, the Bladed Scarf is more versatile than the Starknife. It is a two-handed finessable weapon that deals damage to enemies that grapple you. The Starknife can be used to damage in a grapple, but you're almost always better off trying to get out of the grapple than you are sticking around to do damage.
The Bladed Scarf also has the disarm and trip qualities, which allow builds that want to use those maneuvers an appropriate weapon that helps them accomplish that.
At 2 lbs., the Bladed Scarf is lighter than a Starknife, which the classes that dumped strength will appreciate.
And as for unique magical weapons, the Wanderer's Scarf is good if you're around any undead. Hide from Undead, 1d6 positive energy when striking undead, and a +1 enhancement. Most of what you need in a nice tidy package that you can still wear to fancy parties without drawing much attention.
