Hi There,
Welcome back to the iphone.
Ive been going backwards and forwards between ios, wp and google myself.
Finally decided to come back to the iphone 5 as well about a week ago. Like you mentioned it just works better with all my 'I' devices.
For me it came down to face timing my nephews and nieces and being able to simultaneously download my purchases on all my devices.
I joined a 4g network with EE UK on the 20gb plan after I accidentally realised that you could use the iphone as a wifi hotspot for the apple tv and then still airplay off the iphone at the same time. Smooth as silk. otherwise wifi is a little patchy at home with my normal router.
Just missing my ipad 4 now and i'm complete. I agree with a lot of people regarding ecosystems, I prefer to be part of one as it seems simpler to transfer between devices.
Am definitely looking to see what ios7 brings as well as the next iphone.