One improvement that's much appreciated:
Charging time.
Mine had somewhere in the mid-high 30% range,out-of-the-box.
As someone who switches phones frequently, I like to keep the accessories unopened/intact in the original packaging, to help overall value in case of a sale.
Anyhoo,when JUMPING from the G2 to the M8 earlier today, the clerk was only interested in the phone & couldn't care less about the accessories,or, the box & instruction booklets for that matter.
So, I took her up on the generosity,& am using the G2 charger (1.8A,I believe) & cord.
Only took 1.5hrs to charge from 30% to 100%,a noticeable improvement over the M7.
With the improvement in battery life + quicker charge times, I'll definitely be foregoing the usual charging case this time around.