Consensus seems to be a lot of people on here have a good/great experience with them. Then the odd few like myself.
- Terrible data coverage across London
- Takes ages to normalise/get signal if I come out from the underground
- Indoor is poor a lot of the times
- Don't even bother at London Bridge, Waterloo or Notting Hill Carnival - simply doesn't like large crowds of any sort
- Constantly misrepresents what signal I actually have
- Extremely poor speeds when I try Speedtest, real world performance is fairly good
Unlimited and free 4G are keeping me going.