I second this, my phone is almost unusable 40% of the day.
Worst part is, I cannot roll back because my last iTunes backup was 6 months ago, and for some reason the most recent backup i did before i did the update says my backup is too new for iOS 7.
I can't use 70% of the apps on my phone without crashing, i can't send more than 3-4 consistent texts without messaging freezing up/crashing.
Can't see videos on facebook, randomly crashes. Can't take videos on snapchat at all, completely crashes, Google chrome does not work at all. Voicemails keep popping up randomly hours or days after i delete them. It's extremely frustrating. feels like they just tossed something together and tossed it out there.
REALLY hoping this next update fixes a lot of the stability issues. because right now iOS 8 is about as stable as Linsey Lohan at a crack house.