Some Verizon and Sprint techs say their CDMA iPhones won't work on a GSM network; I just stuck my AT&T SIM card into my former Sprint iPhone 6 and it works great! No lag or messaging problems. 👍😊
I usually buy the device that best fits my needs. I recently changed my service provider and as a result bought a new android phone as my daily driver. So far I am having a good experience; not too much different from my iPhone (which I still use).
Your SIM card contains all your contacts, personal information, etc. It can be put into another device and used to make phone calls. Your SIM card should be protected with a PIN. If it is stolen it should be reported ASAP.
Re: Let`s Hear the problems what people are facing on iOS 10
Fortunately I haven't experienced any problems with the iOS 10 update on any of my devices.
With the removal of the audio jack on the iPhone 7, Apple removed the option to use wired or wireless. I use both (wired and wireless) since some of my audio devices are not wireless. I guess I'll hanging on to my iPhone 6 for a while longer.