I have literally done hundreds of orders with AliExpress, mostly for components, and small circuit board modules, but occasionally for larger stuff. I've had a few issues with transactions, something that I tend to expect, but no more than many eBay transactions. Unless you're going to buy through mainstream places like Digikey or Mouser, the process may not be quite as smooth, that is a fact. In only a handful of cases have I had to "go to the mat" on a transaction to get satisfaction. Frequently, if you have an issue with an order, they will simply refund the money. Shipping stuff back is price prohibitive as a rule, so any deal where you have to return an item without paid return shipping is bound to be a loser.