i use a machine call china or north america, quanlity is excellent, 0.02usd per min or 39.95usd one month unlimited. i think it is worth. i forget the company name. the tele no. is 364-0795.
I also found SCC had this invalid PIN problem recently. But when you enter the PIN again, it worked ok. To be honest, SCC is still the best card I have ever used in these three years. It never ate my money and I like it's binding feature. It connect everytime I dial to Beijing. If they can increase the minutes to the same as DaTang or Rainbow, it will be the perfect card.