Taobao is just a marketplace and it's as legit as it's sellers.
What makes Taobao a much safer place is the fact that sellers have to deposit large amounts of money. It's more than they could get from scamming you, so there's no point for them to risk their deposit.
With an agent, you're almost 100% safe, not only against scams. You also have an extra layer of security against bad quality products.