I agree with you T. As I said above, I'm sticking with Nova Launcher and the two button nav for now.
As for the battery, so far I have noticed a faster discharge but I'm sure it's down to the fact that, since the upgrade, I've been hammering the phone more than usual checking things out. We will see over the next few days.
Overall, I'm quite happy with 10.
One thing I thought was odd, I now have more free storage than before. I thought it would be less. Maybe it's because the fresh instal has cleared out some dross.
One thing that I find annoying is that you no longer have the battery percentage shown on the lock screen.