If it were me, I wouldn't trade the White Cement IV's straight up for the PB Yeezy's. I think the IV's are a better shoe, but the Yeezy's will command more if you were to sell both. White Cement IV's would have to add a decent amount of cash, imho.
If you look at your location, it says "Shoes are only as valuable as [you're] willing to pay." Apply this to your trade question. If you think it's worth it, it is.
The concept at work here is the law of marginal utility, which states that as someone increases consumption of a product, there is a decrease in the marginal utility that person gains by consuming an additional unit of said product, assuming consumption of other products remains constant.