Today is day 6 of my iPhone 6 experience.
Here is what I have learnt so far :
It is bigger which takes more re adjusting than you'd think
The design has improved significantly
Camera is better
Battery seems better ( my pet hate with the 5 & 5S )
IOS8 updates all make sense
It doesn't overheat as much
It is very slippery, make sure you get a case
I won't be buying the watch
Thankfully it uses same hardware as the 5S (apart from case which is why you will need a new one)
My inbox still has 20,114 (and counting) unread emails
That's about it.