I bought an iPhone 5s from that ali, I spent 365 euros, it came in good time, at least for China and was well packaged. I didn't use it immediately as I had no cover to protect it, after a week I started to use the phone and noticed that most of the time I had no cellular/network coverage. I messaged the seller to ask if they could help, I was told to restore the phone and I did so through iTunes, long story short the iPhone no longer works as it wont reactivate through the apple servers. And because I'm outside of the 15 day window to open a dispute, I am left with a very expensive brick.
I would not purchase anything costing more than 5 euro from this site