No 4G in my main areas of use and when I did a couple of speed test yesterday around midday the speed was around 0.4Mbps. Too slow to use some of the streaming services I want to use. It also not just the speed but how unreliable the connection it. Seems to switch between H+, E or G in the same place even when the signal appears to be good and as soon as this happens data dies.
GiffGaff run off the o2 network so effectively it is tethering the signal, therefore it will be slower than the O2 network as they prioritise their own customers and contract members before GiffGaff customers.
Why else would they call everything O2 priority? hahaha, but all in all I've had no problem with GG so far, its been decent speeds.