When it comes to knives, "all positive reviews" on ebay is meaningless. I wouldn't be at all surprised if there are sellers on eBay with all positive reviews who sell counterfeit knives (they might even buy them from Aliexpress). "All positive reviews" could mean that buyers received their purchase, prompt shipping, etc, but many people who buy knives on eBay either don't know the difference between real and counterfeit knives, or they don't care if they're buying a counterfeit, or they are like you, and they don't know that counterfeits exist.
It's entirely possible that the knife you bought is a counterfeit. I'm not saying it is, but it is a well-known fact that counterfeit knives get sold on eBay.
As far as Aliexpress, you'll likely get exactly what you order, but what you get will very likely be a counterfeit. But I strongly recommend against ordering anything from Aliexpress.
I also strongly recommend being very careful about buying knives off ebay.