According to what I read these Chinese iPhoneys have one virtue. 
They may not be very good phones but they are the cheapest way to get a wifi equipped PDA -- so that you can use internet at home or in cafes without the annoying cost of using cellphone access. 
In the UK at least, it's hard to find a Pay As You Go phone with wifi so you either have to go on contract or buy secondhand  -- or pay serious money for a SIM free new phone.