I moved from the SGS2 X, same model as the tmo Hercules, I thought I was alone in the battery issue until I read this thread.
I'm running the Telus i-747m, exact same issues mentioned in this thread, exact same battery life as the op.
Yesterday I went back to my store, showed them the issue, they exchanged the battery agreed that something was up with my current one, they said try the new one for a few days and if it's still an issue next week, they'll give me a new phone.
As a note; my roommate and I both got the S3 at the same time, same model, same carrier, his doesn't have this issue, or at least not to the same noticeable degree.
What made me go back to the store, yesterday my phone was on the charger at 100%, I got an incoming call, was on the phone for 15 seconds, hung up, 30 minutes later, I left the house with the phone in my pocket, 10 minutes later, turned on the phone, it was down to 93%, there were no active applications, and nothing using ram but the android system.
I've had several phones, this really doesn't seem normal.
I'll report back once I get 2-3 days on the new battery.