My 7 Plus doesn't hiss or freeze. It's battery is about on par with what my 6s Plus was under iOS 9.2.5 (about 6 to 8 hours of usage depending on location and proximity to cell tower), which isn't that great, but it lasts me through the day unless I do something like game on it.
I restored my 6s Plus backup on to it about a week ago (got it release day).
So from what I have been hearing and reading it's a total crap shoot whether you may or may not get a "good iPhone 7"?
If this was a $25 item I'm OK with it. It doesn't work I throw it in the trash. But an $800 item is a different animal. I don't want to buy an $800 device and "hope" mine doesn't exhibit issues that will cause me hours and hours of trouble shooting. And to top it off I may or may not be able to fix it.
My iPhone 6 running 9.3.5 works perfectly. The battery life is great. It never freezes and I have never experienced any "hissing" of any sort. Of course I don't have many childish Emoji which I guess is OK.
i've had iPhones from Day 1 and never had issues like those being reported. It's flat out ridiculous. What kind of lame testing does Apple do?
I'm sure Apple will figure this out eventually and frankly I'm a little mad at myself for getting sucked in to iOS 10 and the first release. Also I usually wait a minimum of one month before purchasing their new hardware to avoid things like this. Because of the AT&T promotion I jumped on the band wagon way too quickly. So, shame on me.