For what the watch cost, that is not very good battery life, in my opinion. Get the battery to 12 hrs and I will buy.
You're working out with music for a full 12 hours? What type of super-human athlete are you?
I work out with music 2 hours a day. That is a lot with a full time job and a life. My watch has 30-50% battery left by the end of an 18 hour day.