I have the same pump and like you I have nothing too special to say about it other than it is reliable and not complicated. Before this pump I had a Deltec Cozmo. I loved it for a while, but then all of a sudden it stopped working at night. I had two DKA's that required hospital stays within two weeks for unexplaned shutoffs. I really had no explanation for it. Than I received a letter form Deltec telling me about a malfuntion with the model I had that would cause the pump to stop delivering insulin if I left it alone for a period of time (as I would sleeping). They wanted me to sign a recognition form and mail it back. I refused to sign anything and quickly switched to the Minimed. I planned on speaking to a lawyer to try and get Deltec to cover my hospital stays but never really got to it. Anyways, I have had zero problems with my Minimed since.
As for your second question, there are many reasons why people don't use pumps. For one, many people cannot handle the freedom that comes with a pump. I myself struggled with the pump for a long time, and nearly quit testing. Additionally, many people fear having lows at night that they do not notice and having an insulin delivery system attached to you. As a previous commenter put down, it is not for everyone, but if it works for you thats great! Hope this helps.