Surprisingly easy to use. I had no trouble and the email with the unlock codes came within 5 minutes. I was unlocked in less than 15 minutes. (I was cautious to read all instructions because I had made the mistake of typing random numbers in the unlock codes and I only had 5 or 6 tries left.) GSMLiberty worked on the first try. They send 3 different possibilities based on carrier etc but instructed on the web which one to use. I have Storm 9550 originally locked to Verizon. Cost was just $7.95 USD.