I am using E-Trade. Have been very satisfied with their trading platform, very fast.
I have made some trading errors, buying instead of covering my short position. This made me lose quite a significant amount of money.
The trading fees are still at $10. However, I do not mind it as E-TRADE has very good service. Service representatives respond immediately to any request.
Furthermore, E-Trade gives out a debit card which I can use to draw money from any ATM at no charge, all charges are waived by E-trade.
The only con is the higher trading fees, as compared to Fidelity or Charles Schwab or Sogotrade (the cheapest!).
