When will
learn, do Developers really test things out or do they just have fun with the new features and not worry about important things like Battery life.

When willlearn, do Developers really test things out or do they just have fun with the new features and not worry about important things like Battery life.
Battery life seems to be about the same as in iOS 7.
Of course the first few days especially with app updates on top of the OS update we are using the phone more and more trying things out, configuring things, etc., so clearly that will result in faster battery drain even if it seems like you weren't really doing anything different.
My 5s seems worse. Rest network settings.
Doesn't matter as my 6+ will be in hand tomorrow.![]()
To be fair you bought an iPhone 5s with iOS 7 (or 5 with iOS 6), the operating systems those phones were built for. Apple made no promise of performance on future iOS versions for old hardware.
If a new OS comes out built for newer hardware that can handle it better then either keep your older device on the OS it came with or take responsibility if you took a chance upgrading and it didn't work out for your hardware.
Grayscale won't really do anything for the battery as iOS devices use screens that take up the same amount of power whether they display a dark color or a bright color or only some colors and not others.I have updated iOS 8 on my iphone 5 16 GB using iTunes and it works fine. I like the new gray scale mode. When I was down to battery life of 25% I switched to gray scale mode and it seemed to prolong battery life .Has anyone else noticed this?
To be fair you bought an iPhone 5s with iOS 7 (or 5 with iOS 6), the operating systems those phones were built for. Apple made no promise of performance on future iOS versions for old hardware.
If a new OS comes out built for newer hardware that can handle it better then either keep your older device on the OS it came with or take responsibility if you took a chance upgrading and it didn't work out for your hardware.
What apple should do in this case is then allow you to revert, they upgrade you and cripple your phone hoping you'll buy a newer model