What are "Peninim"?
Rashi: They are pearls.
How are they better than Peninim?
Malbim: This explains "Keshu Musari v'Al Kesef" (10). Something bought for Kesef, even if it is pearls, which are precious, better than them is what one buys with Musar ha'Chachmah, i.e. Chachmah. It is a Kinyan in the Nefesh. Even though one can buy with Kesef things that the body desires, e.g. tasty foods and indulgences. For Chachmah, one must cast off all bodily desires and muzzle all its lusts. Trading bodily desires for Chachmah, he gets something dearer and more elevated than all of them.
Malbim: That verse is "Yekarah Hi mi'Peninim" - it is worth more. Here it says Tov. The Tov of pearls is that they give grace to those who bear them; it is only in the eyes of people. Via Chachmah, one gets grace in the eyes of Elokim and people.
What is the meaning of "Lo Yishvu Vah"?
Rashi: They do not resemble its value.
Here it says "v'Chol Chafatzim Lo Yishvu Vah." Above (3:15) it says "v'Chol Chafatzecha Lo Yishvu Vah" - this implies that Cheftzei Shamayim do equal it!
Refer to 3:15:4:1-2.