i had my ATT for 4 years up until February of this year(tytn2 and curve). Sometime in December the network took a turn for the worse in NYC. I would have many dropped calls and calls going straight to voicemail. After 2 months of that, i ended up switching to Verizon as i couldn't even be on a conference call without getting disconnected. i tried a new phone, sim card, battery.... none of which resolved the issues. it was upsetting because i really liked ATT(and my Tytn2). but something definitely changed. and it seemed to happen at the same time as the iphone 3g came out.