Used GG for the last 6 months. Really wanted to like it but I was frequently struggling to make calls, even when the phone was showing full signal strength. Initially thought it was my phone at fault.
Internet was a real pain as it would often not work. Google Maps would never work despite four bars of signal, so navigation often stopped and would not display the maps for many minutes.
Absolutely awful. Moved to a mainstream provider and have had seamless calls and internet for the last month or so. To be honest moving to a different provider has made me realise how crap GG was.
This thread is interesting, because when I moved to GG, the overall feedback was positive.
For me, GG went down the Gary Glitter just over a year ago. Went from a pretty good, if somewhat quirky, provider into a amateur, unreliable, useless provider. The problem is, if you sing their praises on their forum, they give you money, which skews a lot of people's perception... ...and even users become almost blind to the problem.
About a year ago, I moved my primary phone to EE (after trying PAYG on all networks bar Voda (no signal here), which has been shockingly brilliant. Granted, I now pay a tenner a month for 1.1Gb data, 200mins and unlimited txt, whereas with NiffNaff I paid £7.50 for 250Mb data (pointless having more, as it never worked anyway), 200min, unlimited text.
Slowly, I've moved all my others, along with Mrs TB, to EE, except the telematics in the MV6. That needs to stay O2 or Voda based, and NiffNaff is the cheapest O2 based provider I can find.
I rarely ever have trouble with calls - the occasion one going to VM when I know I've had a signal, but I had that on O2 as well. It was just data, which was utterly hopeless.