I too had the Sleep of Death issue, while hoping for software updates to fix it I waited 20 days and dealt with 3 battery pulls per day. Finally exhanged the phone for a new one. Zero battery pulls in 20 days!!!
To the best of the salesman's knowledge (went to 3 different Sprint stores to discuss it) it is a hardware issue. I had the battery tested on the bad phone and it checked out OK.
My advice to anyone with the issue, just return it.