Xao Island of Iron and Silk is a great product, as a stand alone product, you could even just use it to get inspiration for an asian setting. As part of Exodus, this offers an exotic land to visit as it seems the island of iron and silk don't have any presence for all the other races of Neo Exodus.
As mentioned in the pdf, a lot of feats were made during 3.5 and were not updated, so they are mostly just there to serve as inspiration, I could see some of them turned into traits even or some of them already have PF equivalent versions.
Since it is mentioned in the NeoExodus campaign setting that sometime foreigners stop there (well people from the regular setting basically), I would have wanted to see how they deal with these foreigners. I can imagine that people talking about strange technology, planes and etc...probably affect their society, a bit. (Maybe related to how people are often found to be mad coming from there)
Anyway beside that, it's a great product, just couldn't give 5/5 since technically the mechanics are not 100% PF comptatible with the feats.