It's BETA 1. Many many Beta 1s have had less than ideal battery life. And in fact I see no noticeable difference on a 7 Plus vs. 10.0.1.
People need to wait WELL over 1 day to analyze battery life while the phone settles down fro the update/recaching everything. And betas are for DEVELOPERS for a reason and NOT for a primary device; not battery life hunters who have no business being on a beta and then whine about battery life and how terrible Apple is.
Hissing is not a major "issue" as made out to be any more than the fan turning on on your computer. Im sure they will address it at some point via software but the phone has been out all of 7 DAYS total. It's not #1 priority.
Sheesh, people need to relax.