After leaving O2 for Vodafone a couple of years ago when O2's network seemed to have reached breaking point I'm finally considering making the switch back. O2 fought the PR fires of their network congestion with bold claims about investment in the network, so I'm interested - have you seen improvements? What are your current thoughts of O2 for the iPhone 4S compared to the competition? I live in Canterbury, and the city, being rather tiny and home to many old buildings, and surrounding areas have rather poor 3G coverage. When I was with O2 for the iPhone 3G and S, I rarely if ever saw 3G. Then O2 declared they were to roll out 3G900 (3G in the previously GSM band at 900MHz, known for covering greater distances and building penetration), and recently the O2 coverage map has come alive with 3G all over the place. I've blogged my early experience here: http://www.talk3g.co.uk/entry.php?331-Living-the-3G900-dream Any particular qualms or concerns you have with O2? Having been liberated from having to use their network when iPhone exclusivity ended it seems odd to be choosing to go back. There has to be a catch Thanks!