Better than 'King of Thieves'. Hell, only decent Disney sequel.
Multiple reasons:
1) it still features Jafar, the villain in the third movie was hardly menacing at all.
2) builds a story around all the original characters, and the new characters that were introduced played a small part. Abis Mal is a passable new character imo, redeemed by the comedy he brings with the interactions with jafar and the fulfillment of his wishes.
3) the characters are still likeable, in the third they aren't at all. Also, the characters in the third changed in nature considerably, Aladdin turned into your run in the mill hero and Iago's good nature has disappeared completely. Not to mention the horrible voice-acting in the third.
4) the animation is better( though not on par with the original obv.)
5) features a good song (Let's forget about Love), contrary to the third.
I rest my case.
This doesn't mean I'm blind to this one's flaws, it's WAY too short (69min, omg) and of course Robin Williams is missed (though I don't think Dan did a bad job).
...I am lost, I'm no guide, but I'm by your side...