I never had Wifi issues but cell data has been terrible. When I'm not on wifi, only iMessage and Facebook work, the rest all say no internet access. Not sure what's up with that. My wife updated her phone and has the same behavior. My co-worker as well. Not sure why I'm not seeing more complaining about this. We all have T-Mobile.
I hope this update addresses that issue because as of now, when I'm not on wifi, my phone is basically useless for data. Already tried reset network settings, it fixes the issues temporarily and then it comes right back. A reboot may or may not fix it for a little while as well. No carrier updates waiting to be installed.