Phone 1 - the brightness kept randomly setting itself to minimum. This made navigating by touch screen to get to the settings/brightness to bring it back up to normal brightness, well, shall we say 'challenging'!
Phone 2 - replacement was DOA
Phone 3 - while in the process of trying to find a fix to stop that damn wifi network notification screen from popping up all the time and constantly interrupting whatever it was you were trying to do (and despite having the Notifications set to Off), Orange suggested a Factory Reset. At which point in time, wi-fi stopped working completely.
Phone 4 - replacement was DOA
Phone 5 - replacement exhibits exactly the same wi-fi notification screen.
And please, don't get me started on the drongo's at Samsung who wrote the Kies software for the Mac that contravenes virtually every recommended programming practice for the Mac including disabling you from being able to do anything else on your Mac while the Ace firmware is being updated. That and the useless Kies wifiagent software that fills up the logs with 10 million log entries an hour (well, it seems like it).