Until Apple releases a firmware/software update, new iPhone 4S users experiencing poor battery performance should give this one-toggle solution proposed by iDownload a try:
Go to Settings > Location Services > System Services to see if the purple location icon is displayed up in the status bar. If so, toggle off "Setting Time Zone." The arrow icon should now disappear.
According to iDownload, testing this simple settings change on 4 different iPhone 4s handsets, a 4G model, and even the 3GS resulted in improved battery life, as illustrated by Oliver Haslam's screenshot below:
Seems an easy bandage solution for now. We'd love to hear back from other iPhone 4S users experiencing the issue and report back if this toggle setting made a difference.