iOS 10 is out and has been making a splash with new home screen unlock method, new to view your messages, and people unable to find the “shuffle” button in the music app. Granted iOS 10 has a lot of shiny new features and polished up old features. More people upgraded to iOS 10 faster than iOS 9
A major software upgrade like iOS 10 and the upcoming macOS Sierra has a lot of bug issues currently unknown to Apple and other developers. Regardless of how many betas it went through there will be bugs that will pop up once released to the public and installed by early adopters. For example shortly after iOS 10 was released many early adopters were unable to their phones at all which caused Apple to immediately release a quick patch barely hours after it released the upgrade.
During the beta testing phase the pool of devices the software is tested on is limited and doesn’t accurately reflect the devices used by millions and millions of iPhone users across the globe. While two people may have the same model of iPhone, how they use it, the apps, and the content they have on it vary extremely. One person may just use their iPhone for YouTube, Twitter, email, and driving directions while the other user has almost a hundred apps from social media, games, productivity, and more; all of which affect the iPhone in different ways.
Instead wait until the beginning of October after Apple releases one or two minor patch updates such as 10.0.2 or 10.0.3. Waiting until October before updating lets the early adopters discover the bugs (the hard way) for Apple to patch. An added benefit to waiting is that almost all the apps you use should be updated by their developers and fully compatible with iOS 10 by then.