I bought the Power Cover a few weeks ago. I've had mixed results with battery life. I seemed to me that it was draining faster than usual. I wasn't sure that I would keep it or not since it was $200 and it seemed like I was just getting 1.5-2 hours. I'm on a business trip where I'm in a meeting all day. I decided to give it another try before making a final decision on whether to return it or not. I started the day at 8am this morning with 100/100% for both batteries. After 4.5 hours, my Power Cover has fully drained. My SPro2 has been on constantly the whole time except for 10 min breaks every hour. I've been doing email, PPT, note taking, and web surfing (when no one is looking like now). So, for me, it looks like I will hang on to the Power Cover.