Have purchased USA AT&T SIMs from them on a number of occasions, no problems. But don't purchase pre-paid credit from them, they charge $80 AUD for a $45 US recharge. On today's exchange rate it should be about $59 AUD. They caution about problems using your creit card to purchase credit direct from AT&T, rubbish, I have had no problems either here or in the US. I have a both Coles and 28 Degrees credit cards on which i pay no foreign trnasaction fees. even if i did it would be cheaper than buying from DataGO.