About battery life, here is how my phone behaves, one month after the upgrade.
Battery life seems to be better. Charge decreases slowly, but is a little bit erratic.
Usually I charge my phone when the battery is at about 40-60% of charge.
The last time I let it go, just to see how much battery life I could get.
On the 6th (!) day, the battery was at 43%, at the end of the day.
When I woke up, it was at 13%.
That morning was 7 days and 1 hour since the last charge. OK, I just sent some SMS, had a few calls, checked my emails on 3G maybe every morning, but that’s all. Airplane mode every night.
Before the upgrade, the battery level was more linear. It usually decreased by 10-15% a day (I put it on charge every 4 to 5 days).
I think it’s nice for a 4 years, 5 month’s phone (original battery).
I just have to charge before it reaches 40%, just to be sure.
I a really have a new phone, so glad !