Iphone 4S iOS 8 wifi problems

I upgraded my 4S to iOS 8 the other day, and have been having some pretty irritating issues

1. Wifi often will not work at all. Sometimes it won't connect (most of the time), and does not find any devices at all and just says searching. If i try go into the wifi settings screen the screen goes grey over the wifi button to confirm I've touched that option but then freezes up and does not open the page. Other times if I use the quick menu to select wifi its greyed out and says wifi is not available. If I reset my network settings that remedies the issues briefly on some occasions. other times if it will connect to wifi no data will transfer (tried several networks).

2. When my battery gets to about 25% my phone starting freezing up, and the wifi issues generally get worse. If i plug the charger into the phone, it will not recognise it at all. if i try to turn the phone off I can't, as it won't bring the shut down screen up. the only thing i can do is to select and both both buttons to force the phone off and then plug the charger in, which then recognises the phone and restarts.

I strongly advise anyone who has not got iOS 8 yet to hold off until later releases

Can anyone shed some light on these issues, or are experiencing similar issues?