Had my first problems ever with my iphone 5, after the 8.0.2 update. Phone was ultra-reliable beforehand, has been quirky since.
Sometimes drops calls, or I don't hear the other person.
Siri wouldn't respond to me at all today - gave me an error message saying she was unavailable.
Tonight all of my data was stuck - nothing receiving or sending. I had to go in and "delete network settings" to get it to return. Couldn't send/receive emails, nor texts. Could still make phone calls.
Battery life appears a little worse. I went back in to settings and tried to remember which background refreshes, notifications, and privacy settings I had set to "off" since it appears some reverted back to "on" since the update.
Only positive change I noticed - on the phone calls I received today, I didn't have to say "Hello" more than once. I used to have a terrible lag between hitting the answer button and having the caller be able to hear me.
Hope it's not a sign of things to come, hoping the network reset (once) does the trick.