Is there perhaps a way to report that to Apple? I seriously would report to them about the battery drain before many angry consumers do to the point that they switch away from the iPhone.
Knowing Apple, they'll probably fix the battery issues in a iOS 8.1 update. Surprisingly, the battery only drains when I turn on cellular (meaning out of airplane mode, not even with 3G/LTE on). On airplane mode the battery life is obviously better - on par with iOS 7, but phones are not on airplane mode most of the time.
For some reason, my Wi-Fi reception seems to be quite 'bad' compared to iOS 7. It still displays 3 solid bars and multiple speed tests show similar performance, but my apps that require the web including Safari seem to take quite a bit longer to load stuff.
There are some pesky OS glitches. For example, the music app often overlaps the "now playing" with the list view (3 lines). Sometimes cut/copy/paste options just do not appear. iCloud Photo library is in quite a messy situation. Editing older photos will cause the photos app to crash. Apps not updated to iOS 8 yet which have access to photo libraries will be affected (such as whatsapp) because the central photo album is gone. This is what I mean (I have about 250 photos stored in my iPhone):
However, that's not to say iOS 8 is crap. There's quite a lot to look out for, such as when developers update their apps to support extensibility (can't wait for SwiftKey). The quick reply messaging feature is really convenient, but I just want to say... do not expect an entirely smooth experience after updating to iOS 8.